Predictive modeling of spread in adult-onset isolated dystonia: Key properties and effect of tremor inclusion

BACKGROUND AND PURPOSE

Several clinical and demographic factors relate to anatomic spread of adult-onset isolated dystonia, but a predictive model is still lacking. The aims of this study were: (i) to develop and validate a predictive model of anatomic spread of adult-onset isolated dystonia; and (ii) to evaluate whether presence of tremor associated with dystonia influences model predictions of spread.

METHODS

Adult-onset isolated dystonia participants with focal onset from the Dystonia Coalition Natural History Project database were included. We developed two prediction models, one with dystonia as sole disease manifestation ("dystonia-only") and one accepting dystonia OR tremor in any body part as disease manifestations ("dystonia OR tremor"). Demographic and clinical predictors were selected based on previous evidence, clinical plausibility of association with spread, or both. We used logistic regressions and evaluated model discrimination and calibration. Internal validation was carried out based on bootstrapping.

RESULTS

Both predictive models showed an area under the curve of 0.65 (95% confidence intervals 0.62-0.70 and 0.62-0.69, respectively) and good calibration after internal validation. In both models, onset of dystonia in body regions other than the neck, older age, depression and history of neck trauma were predictors of spread.

CONCLUSIONS

This predictive modeling of spread in adult-onset isolated dystonia based on accessible predictors (demographic and clinical) can be easily implemented to inform individuals' risk of spread. Because tremor did not influence prediction of spread, our results support the argument that tremor is a part of the dystonia syndrome, and not an independent or coincidental disorder.

Reducing Fistula Rates following Laryngotracheal Separation

Objectives:

Laryngotracheal separation (LTS) is an uncommonly performed but highly effective procedure for intractable aspiration in patients with amyotrophic lateral sclerosis and other neurodegenerative conditions. Previously published series have noted rates of postoperative tracheocutaneous fistula formation as high as 1 in 3 patients. This report details the use of a muscle flap–reinforced imbrication technique to reduce the incidence of fistula formation after LTS surgery.

Methods:

All patients who underwent LTS surgery at the reporting institutions between 2004 and 2010 were identified. The principal diagnosis, patient characteristics, the presence of a preexisting tracheotomy, and postoperative complications were recorded. We describe the technique for imbrication closure of the proximal stump with strap muscle reinforcement.

Results:

Thirteen patients (10 male, 3 female; median age, 53 years; interquartile range, 45 to 66 years) underwent the LTS procedure; amyotrophic lateral sclerosis was the principal diagnosis in 8 of the 13 patients. Six patients had a preexisting tracheotomy. None developed tracheocutaneous fistula, hematoma, or wound infection. Two patients required stomaplasty at a later date.

Conclusions:

Strap muscle flap–reinforced imbrication closure of the proximal tracheal stump after LTS surgery allows for a low incidence of postoperative fistula formation.

Vocal cord augmentation with cultured autologous fibroblasts

Bovine collagen is an acceptable agent for vocal cord medialization; however, it produces only a temporary effect. As a foreign protein bovine collagen is susceptible to host collagenase and can induce immune response. Autologous collagen has become recently available, but it is less effective as a medialization agent. The study examines human skin fibroblasts growing in culture. Human skin bioptates were taken from the retroauricular area. Fibroblasts in culture were tested for scar contractility and ability to produce type I collagen (by flow cytometry with labeled antibodies). After five passages in culture the cells produced normal type I collagen, exhibited normal contractility, and did not induce no tumors in nude mice.