Purpose : We evaluated the results of surgical treatments for lumbar spinal canal stenosis (LSCS), listhesis, and instability in 75-90 year old elderly patients (EP) and 65-74 year old pre-elderly patients (PEP).

  Materials and Methods : We examined the Japanese Orthopaedic Association (JOA) score preoperatively, immediately postoperatively, at 6 months and 1 year after surgery, and recently, as well as the recovery rate of the JOA score (JOAS RR) in EP (45 cases) and PEP (25 cases). Operative procedures included 50 cases of laminectomy with foraminotomy [posterior decompression (PD)] and 20 cases of posterior decompression and posterolateral fixation (PD+PLF). Stabilization of joints and bony fusion were examined by lumbar dynamic X-ray and computed tomography (CT). Between the EP and PEP groups, and each operative method, JOAS RR joint stabilization, bony fusion, and the complications were investigated.

  Results : In both EP and PEP groups, the JOAS RR was high and there was no significant difference between PD and PD+PLF. A high JOAS RR was maintained for a long time after surgery in both groups. In the EP group, there was no significant difference in the RR 6 months after surgery between PD with and without instability, and severe osteopolosis. However, JOAS RR 1 year after surgery and recently was significantly lower in PD with instability than in PD without instability. Although PD+PLF achieved bony fusion in the EP group, the rate was lower than that in the PEP group, and the stabilization rate of the joints was high in both groups. In PD+PLF, the JOAS RR of patients undergoing joint stabilization was not significantly different from that of patients undergoing bony fusion 6 months and 1 year after surgery.

  Postoperative complications included transient delirium, urinary tract infection, and pneumonia in eight (15.4%), three (5.8%), and one case (1.9%), respectively. Delirium occurred more frequently in the EP than in the PEP group.

  Discussion : Both the EP and PEP groups had good surgical outcomes despite the operative procedures. Early ambulation should be promoted to avoid postoperative delirium and urinary tract infections. In EP, PD in patients with mild instability and without severe neurological symptoms due to instability achieved good outcomes. In both the EP and PEP groups, PD+PLF achieved a high JOAS RR and a high rate of joint stabilization. For cases with mild listhesis and instability, PD+PLF surgery should be justified for EP due to joint stabilization.