Can diffuse reflectance spectroscopy identify shuntodynia in pediatric hydrocephalus patients?

Abstract

Significance: Shuntodynia is patient reported pain at the site of the implanted ventriculo-peritoneal (VP) shunt. Pediatric hydrocephalus requiring shunt placement is a chronic and prevalent standard of care treatment and requiring lifetime management. Shuntodynia is a subjective measure of shunt dysfunction. Quantitative, white-light tissue spectroscopy could be used to objectively identify this condition in the clinic. Aim: Pediatric subjects were recruited for optical sensing during routine clinical follow-up visits, post VP shunt implantations. Acquired optical signals were translated into skin-hemodynamic signatures and were compared between subjects that reported shuntodynia vs. those that did not. Approach: Diffuse reflectance spectroscopy (DRS) measurements were collected between 450-700 nm using a single-channel fiber-optical probe from (N=35) patients. Multiple reflectance spectra were obtained by the attending physician from regions both proximal and distal to the VP shunt sites, and from a matched contralateral site for each subject. Acquired reflectance spectra were processed quantitatively into functional tissue optical endpoints. A two-way, repeated measures analysis of variance (ANOVA) was used to assess whether and which of the optical variables were statistically separable, across subjects with shuntodynia vs. those without. Results: Results showed that vascular oxygen saturation was significantly lower in subjects reporting shuntodynia, when measured proximal to shunt sites. Subjects with shuntodynia also had lower total hemoglobin at the shunt site relative to distal sites. Both patient groups showed higher tissue scattering at the shunt sites in comparison to the contralateral sites. Conclusions: Optically derived hemodynamic variables were statistically significantly different in subjects presenting with shuntodynia relative to those without. DRS could provide a viable mode in routine bedside monitoring of subjects with VP shunts for clinical management and risk assessment of shuntodynia.