Concurrence of Calcium Pyrophosphate Deposition Disease in Patients Undergoing Surgery for Degenerative Spine Conditions: A Case Series and Systematic Review.

Background Calcium pyrophosphate deposition disease (CPPD), also known as pseudogout, is a crystal-induced inflammatory arthropathy that commonly affects elderly individuals. Spinal involvement is considered rare or perhaps underdiagnosed. The objective of this study was to report our institutional series of patients who underwent spinal surgery for degenerative disease and whose intraoperative samples confirmed the presence of CPPD. We performed a systematic review of the clinical and radiological features and outcomes of patients who underwent surgery for degenerative spine problems with a subsequent diagnosis of spine CPPD. Methods This systematic review was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Results Two hundred and eleven articles from electronic databases met our search criteria for the systematic review. Thirty-seven clinical studies comprising 153 patients aged 23 to 83 years were included. Of these, 68 were male, and 85 were female. A total of 33.7% involved the cervical region, 16.2% involved the thoracic region, and 50% involved the lumbar region. The common comorbidities included hypertension, dyslipidemia, diabetes mellitus (DM), and cardiac and renal issues. The common radiological features included nonspecific degenerative changes, an epidural mass, and calcified masses, among others. The most common intraoperative finding was chalky white deposits. The vast majority of patients had good postoperative outcomes. Our institutional case series included six patients. These were analyzed and reported separately in the text.  Conclusions Spinal CPPD is likely much more common than we currently report, primarily because it is underdiagnosed or misdiagnosed for other pathologies. This review investigated the epidemiology, presenting features, imaging, histopathological, and intraoperative findings of this disease. Future prospective studies should focus on establishing standardized diagnostic criteria combining preoperative imaging characteristics with intraoperative findings to improve recognition of spinal CPPD. Additionally, investigations into optimal medical management strategies for patients with concurrent CPPD and degenerative spine disease who may not require surgical intervention would be valuable.