Introduction. The literature of fusion surgery for back pain relief in “mechanical” back pain reveals inconsistent results and in the majority presents only a vague description of these syndromes. From a retrospective cohort experience reported with concurrent survey PROM outcomes, we describe the results of open PLIF reconstruction for a select group of mechanical back pain patients who have mono- or bi-segmental discopathy on MRI imaging, a clinical history of repeated severe and disabling acute mechanical back pain symptoms, and the irregular lumbar motion pattern in returning erect from the flexed position known as the “instability catch”. 

Methods. The senior author (DAB) in midsummer 2015 began to offer smaller fusion procedures to selected patients on an overnight-stay basis using a standard perioperative care protocol. For practice audit, in December 2020 a mailed survey questionnaire requesting VAS pain scores and SF-36 physical function scores was sent out to all 111 patients who had been treated this way, which group included 30 cases of ILDDIC. We report here on the success of open PLIF reconstruction in achieving back pain relief for these patients.

Results. Some 24 of 30 patients returned the mailed survey questionnaire, and the remaining six could not be reached. All 24 reported significant relief of back pain and improved physical function. 

Discussion. The diagnosis of ILDDIC requires both imaging and clinical correlates and may define a subgroup of the mechanical back pain population uniquely suited to achieve pain relief through lumbar fusion. Internal Lumbar Disc Degeneration with Instability catch “ILDDIC” may be one subset of these patients who are uniquely benefitted from spine stabilization.