The Role of Simultaneous Medical Conditions in Idiopathic Normal Pressure Hydrocephalus

Idiopathic normal pressure hydrocephalus (iNPH) is a chronic neurologic syndrome that affects the elderly population in a context of concomitant medical conditions. The aim of this study was to understand the significance of comorbidities using 4 validated and specific clinical scores: Cumulative Illness Rating Scale (CIRS), American Society of Anesthesiologists (ASA) score, Comorbidity Index (CMI), and Charlson Comorbidity Index (CCI).

From 2015 until 2019, the Bologna PRO-Hydro multidisciplinary team selected 63 patients for shunt surgery. All comorbidity scores were collected during preoperative anesthesia evaluation. Positive shunt response was defined as an improvement in overall disability (assessed with modified Rankin Scale [mRS]), in risk of fall (assessed with Tinetti Permormance Orientated Mobility Assessment, Tinetti) and in INPH specific symptoms (assessed with INPH Grading Scale, INPHGS).

Patients with elevated values of CIRS had worse performance in gait and balance at Tinetti scale, both before (P = 0.039) and after surgery (P = 0.005); patients with high values of CMI had inferior values of Tinetti at baseline (P = 0.027) and higher mRS after surgery (P = 0.009); ASA 2 patients had better postoperative Tinetti scores than ASA 3 patients (P = 0.027). A positive or negative shunt response was not significantly correlated with patients' preoperative comorbidity scores.

Patients with multiple comorbidities have a worse preoperative condition compared to patients with less concomitant diseases, and the proposed comorbidity scores, CIRS in particular, are useful clinical tools for the anesthesiologist. Comorbidities, though, do not impact overall postoperative outcome.