The Role of Calcium Pyrophosphate Dihydrate Deposition in the Postoperative Outcome of Lumbar Spinal Stenosis Patients

STUDY DESIGN: Retrospective study. PURPOSE: This study aimed to investigate the association of surgical intervention with clinical and quality of life (QoL) outcomes in patients who underwent posterior spinal surgery for lumbar spinal stenosis (LSS) with spinal calcium pyrophosphate dihydrate deposition (SCPPD) versus that in those who underwent the surgery for LSS without SCPPD. OVERVIEW OF LITERATURE: Calcium pyrophosphate (CPP)-associated arthritis is one of the most common types of arthritis. The clinical outcomes are well studied in CPP-associated arthritis of the appendicular joints. However, few studies have investigated SCPPD. METHODS: A single-institution database was reviewed. LSS patients were categorized as those who did and did not have SCPPD, based on histologic identification. Clinical presentations and postoperative results were analyzed. Disability and QoL were assessed using the Oswestry Disability Index (ODI) and the 36-item Short-Form Health Survey. RESULTS: Thirty-four patients were enrolled, with 18 patients being allocated to the SCPPD group and 16 being allocated to the non- SCPPD group. Preoperative and postoperative pain scores were not significantly different between the groups (p=0.33 and p=0.48, respectively). The average preoperative ODI score in the SCPPD group was slightly higher than that in the non-SCPPD group (57 vs. 51, p=0.33); however, the postoperative ODI score was significantly lower (15 vs. 43, p=0.01). The postoperative physical function, vitality, and mental health of the SCPPD patients were also significantly improved (p=0.03, p=0.022, and p=0.022, respectively). CONCLUSIONS: Surgical intervention resulted in good clinical outcomes in SCPPD patients. As per our findings, total removal of CPPinvolved tissue is unnecessary. As such, surgery should be performed as indicated according to clinical presentation without considering the presence of CPPD.