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Biomedical subjects

J L Marsh

Publications and source records attributed to J L Marsh.

At least 73 records · Page 4Linked to original sources
PubMed1998

The effect of surgeon experience on velopharyngeal functional outcome following palatoplasty: is there a learning curve?

There is little information in the cleft palate literature concerning the relationship between surgeon volume and clinical outcomes. It is unknown whether such a relationship applies specifically to velopharyngeal dysfunction and the need for secondary physical management of the velopharynx. The purpose of this paper was to explore the concept of an operative learning curve for different surgeons with respect to palatoplasty. Impact of case volume and procedure type on the occurrence of secondary palatal management (the main outcome measure) was assessed. The charts of 472 consecutive palatoplasty patients were reviewed by one speech and language pathologist to determine when the palatoplasty was performed, which surgeon (n = 9) performed the palatoplasty, whether velopharyngeal status was documented at a minimum of 6 years of age, and whether secondary palatal management was prescribed. The results were analyzed by year of palatoplasty, by surgeon, and by number of operations per surgeon to determine total and individual surgeon rates of secondary palatal management. There were 401 palatoplasties (85 percent recovery) with adequate documentation of velopharyngeal status by at least 6 years of age. Palatoplasty rates ranged between 1 and 258 palatoplasties per surgeon. Over the 12 years reviewed, secondary palatal management was performed for 92 patients (23 percent) of the study population. Examination of the proportion of palatoplasty patients receiving secondary palatal management by surgeon and by year showed only one surgeon with a pattern suggesting a learning curve. The proportion of patients receiving secondary palatal management was plotted against the total number of surgeries the surgeon performed. There was a strong relationship between experience and success. The number of procedures this surgeon performed per year increased at approximately the same time as the success rate improved. The categories of "total procedures" and "procedure per year" were highly correlated with each other. Success rates were analyzed by number of procedures performed per year, and there was a clear association between the two variables. To separate the effect of the two variables, a multiple regression model was constructed. The category of "total procedures" was statistically significant in the model, whereas procedures per year was not, suggesting that the key to the dominant surgeon's improvement was cumulative experience rather than frequency of performance of the operation. Palatoplasties performed by high-volume surgeons are more likely to result in better postoperative outcomes (i.e., lower rates of secondary palatal management) as compared with palatoplasties performed by low-volume surgeons. The influence of the surgeon's cumulative experience on improvement seems to be more important than the frequency of performance of primary palatoplasty.

Cleft Palate↗
PubMed1998

Factors influencing accuracy of screw displacement axis detection with a D.C.-based electromagnetic tracking system.

Recent technical improvements and cost reductions in electromagnetic motion tracking systems invite their application to motion axis determination in the surgical setting. After evaluation of the accuracy of a state-of-the-art D.C. electromagnetic tracking system, which generates complete three-dimensional kinematic outputs from just a single receiver, we calculated screw displacement axes (SDA's) from its source data. The accuracy of SDA determination from such source data was evaluated for various rotational increment sizes around a revolute joint. A novel smoothing procedure, customized for this type of source data, was developed, enabling SDA detection from incremental rotations of less than 1 deg, at an accuracy appropriate for intra-operative measurement of human joint motion. Examples of SDA determination are given for motion tracking of a ball joint and of the elbow articulation.

Electromagnetic Phenomena↗
PubMed1998

Salvaging the failed pharyngoplasty: intervention outcome.

OBJECTIVE: This paper reports on the rates of failure of operations (pharyngeal flap and sphincter pharyngoplasty) performed for management of velopharyngeal dysfunction, and outcome following their revision. DESIGN: Anatomic abnormalities associated with unacceptable vocal resonance and nasal air escape following pharyngeal flap and sphincter pharyngoplasty were critiqued. The results of primary pharyngeal flap were evaluated for 65 patients, and the results of primary sphincter pharyngoplasty were evaluated for 123 patients. All patients were treated for velopharyngeal dysfunction. The definition of surgical failure was based on persistent hypernasality and/or nasal turbulence on perceptual speech evaluation, and incomplete velopharyngeal closure on instrumental evaluation, at least 3 months postoperatively. SETTING: All patients were evaluated and managed at the Cleft Palate and Craniofacial Deformities Institute, St. Louis Children's Hospital, a tertiary cleft care center. PATIENTS, PARTICIPANTS: All patients had failed surgical management initially, either with pharyngeal flap or sphincter pharyngoplasty, and all underwent repeat preoperative and postoperative perceptual speech evaluations; real-time lateral phonation fluoroscopy including still reference views; and flexible nasendoscopy of the velopharynx using standard speech protocols. INTERVENTIONS: Revisional surgery for both procedures consisted of either tightening of the sphincter pharyngoplasty or pharyngeal flap port(s) or reinsertion of the sphincter pharyngoplasty or pharyngeal flaps following dehiscence. MAIN OUTCOME MEASURES: The main outcome measure was normalcy of velopharyngeal function, i.e., elimination of perceptual hypernasality and instrumental evidence of complete velopharyngeal closure. The rates of pharyngeal flap failure and sphincter pharyngoplasty failure were determined for those patients requiring surgical revision. RESULTS: Thirteen of 65 patients (20%) who underwent primary pharyngeal flap required revisional surgery. Of these 13 patients, eight were managed successfully with a single revisional operation. The remaining five patients (38%) continued to exhibit velopharyngeal dysfunction and underwent a second revision consisting of tightening or augmentation of the lateral ports. Speech results were satisfactory in all patients so treated; however, hyponasality with no other airway morbidity occurred in all five. Twenty of 123 patients (16%) who underwent primary sphincter pharyngoplasty required surgical revision. Of these 20 patients, 17 were managed successfully. For both procedures, the principal cause of failure was partial or complete flap dehiscence. CONCLUSIONS: Rates of primary pharyngeal flap failure are roughly equivalent to rates of primary sphincter pharyngoplasty failure. Pharyngeal flap and sphincter pharyngoplasty failures can be salvaged with revisional surgery, which can provide a velopharyngeal mechanism capable of complete closure. Revisional surgery is usually associated with denasal speech.

Child↗
PubMed1998

Limited value of preoperative cervical vascular imaging in patients with velocardiofacial syndrome.

The purpose of this two-part study was to evaluate the safety of surgical management of speech production disorders in patients with velocardiofacial syndrome without preoperative cervical vascular imaging studies. Anomalous internal carotid arteries have been shown to be a frequent feature of velocardiofacial syndrome. These vessels pose a potential risk for hemorrhage during velopharyngeal narrowing procedures. Magnetic resonance angiography, and other forms of cervical vascular imaging studies such as computerized tomography, have been advocated as aids to surgery by defining the preoperative vascular anatomy. However, it remains unclear whether these studies alter either the conduct or outcome of operations on the velopharynx. In the first part of this study, we reviewed the charts and videonasendoscopic evaluations of 39 consecutive patients with confirmed or suspected velocardiofacial syndrome who underwent sphincter pharyngoplasty or pharyngeal flap from 1978 to 1996. The charts were reviewed to determine (1) the frequency of identification of abnormal pharyngeal pulsations; (2) whether such pulsations affected the conduct of the operative procedure; and (3) whether the presence of pulsations affected surgical morbidity and/or surgical outcome. None of the patients underwent any type of cervical vascular imaging study. In the second part of this study, we surveyed plastic surgeons with numerous years of experience participating on cleft-craniofacial teams, to ascertain practice patterns relating to the management of patients with velocardiofacial syndrome. The questions related specifically to the surgeons' behavior in relation to angiography and their awareness of any cases of surgical morbidity related to the cervical vascular system in patients with velocardiofacial syndrome. We were interested in discerning both how commonly this situation arises clinically and the distribution of the various types of operative procedures in common use. Of our 39 patients, 10 patients (26 percent) had detectable pulsations on preoperative nasendoscopy. Of these, five patients underwent sphincter pharyngoplasty and five underwent pharyngeal flap procedures. Preoperative instrumental and intraoperative clinical assessment of pulsatile vessels allowed velopharyngeal reconstruction in all patients without surgical morbidity. Results of the questionnaire indicated that most cleft surgeons do not routinely order cervical vascular imaging studies for all of their patients with velocardiofacial syndrome. About half of the respondents indicated that their operative approach was influenced by information obtained from angiographic studies. None of the surgeons queried were aware of any cases of surgical morbidity related to the cervical vascular system in patients with velocardiofacial syndrome. Nearly 50 percent of surgeons use pharyngeal flap procedures most frequently, whereas 22 percent of surgeons use sphincter pharyngoplasty most frequently. Results of this study support the safety of sphincter pharyngoplasty or pharyngeal flap procedures in patients with velocardiofacial syndrome without preparatory angiography. These procedures can be performed safely, even in patients having aberrant velopharyngeal pulsations. Given the market cost of magnetic resonance angiography ($1600), one must question the cost-efficacy of magnetic resonance angiography for routine use in the velocardiofacial syndrome population.

Blood Loss, Surgical↗
PubMed1998

Modeling protein homopolymeric repeats: possible polyglutamine structural motifs for Huntington's disease.

We describe a prototype system (Poly-X) for assisting an expert user in modeling protein repeats. Poly-X reduces the large number of degrees of freedom required to specify a protein motif in complete atomic detail. The result is a small number of parameters that are easily understood by, and under the direct control of, a domain expert. The system was applied to the polyglutamine (poly-Q) repeat in the first exon of huntingtin, the gene implicated in Huntington's disease. We present four poly-Q structural motifs: two poly-Q beta-sheet motifs (parallel and antiparallel) that constitute plausible alternatives to a similar previously published poly-Q beta-sheet motif, and two novel poly-Q helix motifs (alpha-helix and pi-helix). To our knowledge, helical forms of polyglutamine have not been proposed before. The motifs suggest that there may be several plausible aggregation structures for the intranuclear inclusion bodies which have been found in diseased neurons, and may help in the effort to understand the structural basis for Huntington's disease.

Amino Acid Sequence↗
PubMed1997

Human hair follicles as a peripheral source of tyrosine hydroxylase and aromatic L-amino acid decarboxylase mRNA.

Total RNA from human hair follicles was reverse transcribed and amplified using primers specific for aromatic L-amino acid decarboxylase (AADC) and tyrosine hydroxylase (TH). Agarose electrophoresis of the amplified products showed reverse transcription polymerase chain reaction (RT-PCR) products of the expected size for both TH and AADC. Sequencing showed that the amplified products matched the known sequences of TH and AADC. This study identifies hair follicles as a convenient, uninvasive, source of the mRNA for TH and AADC. Analysis of these mRNA's may be useful in the diagnosis and investigation of conditions resulting from qualitative changes in the genes that code for these enzymes.

Aromatic-L-Amino-Acid Decarboxylases↗
PubMed1997

Combinatorial signaling by Twisted Gastrulation and Decapentaplegic.

The Twisted Gastrulation (TSG) protein is one of five secreted proteins required to pattern the dorsal part of the early Drosophila embryo. Unlike the Decapentaplegic (DPP) protein that is required to pattern the entire dorsal half of the embryo, TSG is needed only to specify the fate of the dorsal midline cells. Here we have misexpressed the tsg gene with different promoters to address its mechanism of action and relationship to DPP. When expressed in a ventral stripe of cells, TSG protein can diffuse to the dorsalmost cells and can rescue the dorsal midline cells in tsg mutant embryos. Despite elevated levels that exceed that exceed those needed for biological activity, there was no change in dorsal midline or lateral cell fates under any conditions tested. We conclude that TSG does not modulate an activity gradient of DPP. Instead, it functions in a permissive rather than instructive role to elaborate cell fates along the dorsal midline after peak levels of DPP activity have 'primed' cells to respond to TSG. The interaction between TSG and DPP defines a novel type of combinatorial synergism.

Animals↗
PubMed1997

Supracondylar fractures of the femur treated by external fixation.

OBJECTIVE: To determine the results and complications of treating supracondylar fractures of the femur with external fixation. DESIGN: Retrospective follow-up from the time of injury (inception cohort) to an average of thirty-one (range thirteen to seventy-two) months after injury. SETTING: Tertiary care university hospital. PATIENTS: All thirteen adult patients with supracondylar femur fractures treated with the method described were included. There were seven closed and five open fractures and five vascular injuries that required repair. Fractures were chosen for this technique on an individual basis by the treating surgeon. INTERVENTIONS: The femoral condyles were reduced percutaneously or via a medial arthrotomy and stabilized with 6.5-millimeter cannulated screws. Fixator pins were placed from lateral to medial in the condyles and in the shaft above the fracture. The monolateral fixator was applied laterally and stabilized the reduced condyles to the shaft. Initial grafts of bone were used in five fractures. External fixation time averaged 127 days. OUTCOME MEASURES: During treatment we determined the occurrence of complications at the pin sites and the fracture site, the time of healing, and the angular alignment at healing. At the latest follow-up we determined the range of motion of the knee, knee stability, a standardized knee score, and on radiographs the occurrence of arthrosis. RESULTS: Twelve fractures healed primarily. One patient had a fracture site infection and required further treatment before healing. Knee flexion was restricted while in the fixator but rapidly recovered after frame removal. At follow-up (average thirty-one months), the range of knee flexion averaged 111 degrees (range sixty-five to 140). The Iowa Knee Score averaged 87 points (range 75-93 points). Four femurs healed with angular malalignments, shortening, or both. Twelve knees had no detectable arthrosis. CONCLUSIONS: We concluded that in select supracondylar femur fractures, monolateral external fixation is a satisfactory treatment alternative.

Adolescent↗
PubMed1997

Assessment of the AO/ASIF fracture classification for the distal tibia.

OBJECTIVES: The purpose of this study was to assess the interobserver reliability and intraobserver reproducibility of the AO/ASIF and Rüedi and Allgöwer classifications for fractures of the distal tibia, and to determine the benefit of a computed tomography (CT) scan and experience on observer agreement for several fracture characteristics, including classification. METHODS: The radiographs of forty-three fractures of the distal tibia, fourteen of which had CT scans, were assessed by groups of experienced and less-experienced observers. Each case was classified according to the AO/ASIF and Rüedi and Allgöwer systems. Several other fracture characteristics also were assessed. The kappa coefficient of agreement was calculated and used to compare the interobserver reliability and intraobserver reproducibility of the classification systems and to determine the benefit of experience and CT scans. The intraclass correlation coefficient was used to assess noncategoric data. RESULTS: Interobserver and intraobserver agreements were good when classifying fractures into AO/ASIF types and significantly better than that for the Rüedi and Allgöwer system. However, agreement was poor when classifying the fractures into AO/ASIF groups. For most assessments, the experienced group tended to have higher levels of interobserver agreement, but not intraobserver agreement. Viewing the CT scans improved agreement on the percentage of articular surface involved, but it did not improve interobserver reliability or intraobserver reproducibility for either of the classification systems. CONCLUSION: The AO/ASIF classification for fractures of the distal tibia has good observer agreement at the type level, but poor agreement at the group level. Experience tends to improve interobserver agreement, but not intraobserver agreement. Viewing CT scans does not improve agreement on classification, but it tends to improve agreement on articular surface involvement.

Ankle Injuries↗
PubMed1997

Relationship between bone and muscles of mastication in hemifacial microsomia.

The relationship between the bone and muscles of mastication in hemifacial microsomia was studied using three-dimensional volumetric computed tomography scans and image processing techniques. High resolution head computed tomography scans were obtained from 31 patients with unilateral hemifacial microsomia and eight normal patients. Using three-dimensional volume renderings of bone, mandibular deformities in patients with hemifacial microsomia were classified using the Pruzansky system. For each patient, specific craniofacial bones (temporal bone, maxilla mandible) and the muscles of mastication (masseter, temporalis and lateral and medial pterygoid) were segmented bilaterally from the image volume for independent display and volume measurement. Volumes were expressed as the ratio of the affected: unaffected sides. For the masseter and temporalis, the relationship between muscular hypoplasia and osseous hypoplasia in its origin and insertion was studied by plotting affected:unaffected bone volume as a function of affected:unaffected muscle volume for each muscle, bone of origin, bone of insertion triplet. The volumes of the pterygoid muscles were compared with hemimandibular volumes. The precision of object segmentations was examined by repetitive definition tasks, whereas the accuracy of volume measurement was tested by scanning custom-made phantom objects and comparing digital to physical object volume measurements. Volume measurements performed using these techniques were both accurate and precise. In hemifacial microsomia, the extent of hypoplasia of specific muscles of mastication predicted the extent of dysplasia in their osseous origin and insertion. However, the reverse was not true. The extent of hypoplasia of the facial bones did not necessarily predict the extent of hypoplasia in the attached muscles of mastication. Pruzansky grade of the mandible described the degree of mandibular hypoplasia on the affected side, but was inconsistent in its prediction of volume decrease of the other facial bones.

Facial Asymmetry↗
PubMed1997

Surgical management of velopharyngeal dysfunction: outcome analysis of autogenous posterior pharyngeal wall augmentation.

Posterior pharyngeal wall augmentation has been advocated for patients having velopharyngeal dysfunction with a small coronal gap. Nonautogenous augmentation has not been accepted widely because of migration or extrusion of alloplastic implants and resorption of injected materials. Autogenous posterior pharyngeal wall augmentation has been performed for decades by Italian surgeons. A retrospective study was conducted to evaluate the efficacy of this procedure. Autogenous posterior pharyngeal wall augmentation, using a rolled superiorly based pharyngeal myomucosal flap, was performed on 14 patients, between November of 1989 and June of 1992, who fulfilled two criteria: velopharyngeal dysfunction unresponsive to speech therapy and a small (< 20 percent) coronal gap on velopharyngeal nasendoscopy. Of these, 3 patients had prior prosthetic velopharyngeal management, including 2 patients with Robin sequence. All patients were evaluated preoperatively and 3 months postoperatively with recorded (audio-videotape) perceptual, nasendoscopic, and fluoroscopic standardized speech and airway evaluations. The tapes were used for construction of a randomized master tape that was presented in blinded fashion and random order to three skilled raters for independent assessment of numerous perceptual and instrumental parameters of speech. The raters were uninvolved in the care of the patients or this study, and their intraobserver and interobserver reliabilities were known. Preoperatively, the majority of patients had nasal turbulence. All patients had variable degrees of hypernasality ranging from intermittent to pervasive. Parameters rated included (1) resonance (hypernasality, hyponasality, mixed), (2) auditory nasal emission (including nasal turbulence), and (3) visual characteristics regarding velopharyngeal closure. The visual parameters consisted of questions about whether a pharyngeal bulge was present or absent, descriptions of posterior pharyngeal wall movements with speech, level of closure, completeness of velopharyngeal closure, and quantitative descriptions of the percentage of velopharyngeal closure postoperatively. Examiners were instructed to look for a static and/or dynamic projection or bulge (i.e., Passavant's ridge) and, if a bulge was present, whether the level of velopharyngeal closure was on the same plane as the neoposterior pharyngeal bulge. Results of the extramural judgments of these parameters showed that there was no statistically significant tendency for patients' speech to be rated as more normal after the augmentation procedure than before it. We conclude that (1) autogenous posterior pharyngeal wall augmentation does not result in speech improvement and (2) autogenous posterior pharyngeal wall augmentation does not impair the nasal airway.

Child, Preschool↗
PubMed1997

Perception of postpalatoplasty speech differences in school-age children by parents, teachers, and professional speech pathologists.

The aims of this study were twofold: (1) to test the ability of parents and teachers to discriminate the speech of children with repaired cleft palate from that of their unaffected peers and (2) to compare these lay assessments of speech acceptability with the critical perceptual assessments of expert clinicians. The subjects for this study were 20 children of school age (age range, 8 to 12 years) who were drawn from a large population (n = 1282) of patients. All subjects had been referred for palatoplasty to the same tertiary cleft center between 1978 and 1991. There were 16 matched controls. The listening team included parents of subjects (n = 32) and teachers of age-matched school children (n = 12). Randomized master audiotape recordings of the study group were presented in blinded fashion to both groups of the adult raters, who were inexperienced in the evaluation of patients with speech dysfunction. An experienced panel of three extramural speech pathologists evaluated the same recordings. In all parameters rated, both parents and teachers showed a consistent tendency to give the subject children more negative ratings than the control children. Expert raters were sensitive to differences in resonance and intelligibility in the control and cleft palate groups. Results of this study differ from similar previous research, indicating that naive peer raters (similar-age children) were insensitive to speech differences in the cleft palate and control groups.

Adult↗
PubMed1997

Defects in glucuronate biosynthesis disrupt Wingless signaling in Drosophila.

In vitro experiments suggest that glycosaminoglycans (GAGs) and the proteins to which they are attached (proteoglycans) are important for modulating growth factor signaling. However, in vivo evidence to support this view has been lacking, in part because mutations that disrupt the production of GAG polymers and the core proteins have not been available. Here we describe the identification and characterization of Drosophila mutants in the suppenkasper (ska) gene. The ska gene encodes UDP-glucose dehydrogenase which produces glucuronic acid, an essential component for the synthesis of heparan and chondroitin sulfate. ska mutants fail to put heparan side chains on proteoglycans such as Syndecan. Surprisingly, mutant embryos produced by germ-line clones of this general metabolic gene exhibit embryonic cuticle phenotypes strikingly similar to those that result from loss-of-function mutations in genes of the Wingless (Wg) signaling pathway. Zygotic loss of ska leads to reduced growth of imaginal discs and pattern defects similar to wg mutants. In addition, genetic interactions of ska with wg and dishevelled mutants are observed. These data demonstrate the importance of proteoglycans and GAGs in Wg signaling in vivo and suggest that Wnt-like growth factors may be particularly sensitive to perturbations of GAG biosynthesis.

Amino Acid Sequence↗
PubMed1997

Shaggy and dishevelled exert opposite effects on Wingless and Decapentaplegic expression and on positional identity in imaginal discs.

The finding that Wingless (WG) and Decapentaplegic (DPP) suppress each others transcription provides a mechanism for creating developmental territories in fields of cells. Here, we address the mechanism of that antagonism. The dishevelled (dsh) and shaggy (sgg) genes encode intracellular proteins generally thought of as downstream of WG signaling. We have investigated the effects of changing either DSH or SGG activity on both cell fate and wg and dpp expression. At the level of cell fate in discs, DSH antagonizes SGG activity. At the level of gene expression, SGG positively regulates dpp expression and negatively regulates wg expression while DSH activity suppresses dpp expression and promotes wg expression. Sharp borders of gene expression correlating precisely with clone boundaries suggest that the effects of DSH and SGG on transcription of wg and dpp are not mediated by secreted factors but rather act through intracellular effectors. The interactions described here suggest a model for the antagonism between WG and DPP that is mediated via SGG. The model incorporates autoactivation and lateral inhibition, which are properties required for the production of stable patterns. The regulatory interactions described exhibit extensive ability to organize new pattern in response to manipulation or injury.

Adaptor Proteins, Signal Transducing↗
PubMed1997

Personality attributions based on speech samples of children with repaired cleft palates.

OBJECTIVE: This study examined whether or not assumptions made about personality characteristics based on speech samples differed for children with repaired cleft palates (CP) versus unaffected children. DESIGN: Audiotapes of speech samples were presented in random order to blind raters. PATIENTS/PARTICIPANTS: The subjects were 20 children (10 females, 10 males) with repaired CP and 16 control (i.e., unaffected) children (8 females, 8 males). All children were 8 to 12 years of age, Caucasian, living in the St. Louis area, and lower-middle to upper-middle class. The raters were 20 (13 females, 7 males) 6th grade Caucasian students who attend a private school in the area. SETTING: Raters heard tapes in a group setting, but with individual headphones, in their school's cafeteria. MAIN OUTCOME MEASURE: Each speech sample was rated (7-point Likert scale) by each student rater on a variety of personality characteristics based on the "Big Five" personality factors. RESULTS: A factor analysis of the items revealed a two-factor solution, although the factors were highly negatively correlated. No significant differences were found between ratings for the CP sample and the control sample for either factor scale (ANOVA, p = .93; p = .67). Similarly, when the two factors were combined to form a single factor, no significant differences were found between the ratings for the CP sample and the control sample (ANOVA, p = .79). CONCLUSIONS: Overall, it does not appear that children differentially associated personality characteristics based on speech to children with repaired CP versus unaffected children, in the absence of visual input.

Analysis of Variance↗