This is a multi centred (four sites) randomised controlled trial with a total sample of 50 participants after obtaining their informed consent. Participants will attend the pain clinic at the Hospitals for a baseline visit where they will be randomised with a ratio of 1:1 to receive either the Minuteman™ Interspinous interlaminar fusion Implant or standard surgical decompression for the treatment of lumbar spinal stenosis (LSS). Following randomisation arrangements will be made for the participant to receive the randomised treatment. If allocated to Minuteman™ Implant, the treatment will be conducted by the Pain Specialist identified at the site. If allocated to surgical decompression, the treatment will be conducted by the neuro/spinal-surgeon identified at the site. Participates will be followed up regularly for 60 months post implant to assess clinical efficacy, safety, participants function and quality of life of each treatment.