Background: Degenerative spine disease is a common cause of low back pain in people age 65 years or older. Nonsurgical treatment is tried first, but if it is unsuccessful, surgery is advocated. This has special connotations for both underlying disease and the biomechanical characteristics of osteoporotic bone. We conducted an observational study to investigate the clinical and radiological outcome in patients in this age group with poor bone quality and degenerative lumbar instability treated with fusion using perforated pedicle screws augmented with polymethylmethacrylate (PMMA).Methods: We collected prospective data on treatment, outcome, and patient characteristics from our institution's database. The primary outcome was a change in pain and physical function measured by the visual analog scale, the Core Outcome Measures Index, and the Oswestry Disability Index. Control participants were also analyzed for secondary complications such as hardware mobilization, fusion (as apparent on radiographs), and adjacent fractures or adjacent degenerative disc disease.Results: We included 89 patients who underwent surgery between October 2015 and February 2018 at a mean age of 78 years (range, 67-88 years) and were then monitored for at least 12 months (range, 12-40 months). Findings on pain and function questionnaires showed improvement at 6 months after surgery, maintained at the final evaluation; 90% of patients had final score increases of 15 points. No patient developed clinical complications secondary to PMMA leakages. One patient had nonunion and screw breakage. No other patient had clinical or radiological nonunion. Of the control participants, 6 had adjacent disc disease, with 2 of them requiring instrumentation extension. Six deep infections required surgical revision without removal of material.Conclusion: PMMA-augmented cannulated pedicle screw instrumentation in spine fusion effectively and safely treats degenerative lumbar disease in patients who are age 65 years or older with poor bone quality.