Abstract
Introduction: Posterior interbody fusion (PLIF) can be performed for a variety of indications and by a variety of methods. This paper presents a prospective observational study of the outcome for PLIF using an insert and rotate lordotic implant with pedicle screws for the indication of neurological compression caused by segmental deformity.
Methods: Prospective data was collected preoperatively and at regular intervals during the post operative period. Self assessed outcome measures of visual analog pain score (VAS), Low Back Outcome Score (LBOS) and SF12 general health data was obtained at intervals after the surgery. This paper presents the results of a consecutive series who have a minimum of 6 months followup. All surgery was performed by the two authors. Implants used were a carbon fibre composite ramp (DePuy AcroMed), a titanium mesh lordotic cage (Medtronic Sofamor Danek) or a lordotic PEEK spacer (R90, Medtronic Sofamor Danek).
Results: One hundred and twenty eight cases were performed. The mean age was 61.5 yrs(sd 15.1), 63 (49% ) were female and 65(51%) were male. Thirteen cases (10%) were workers compensation. Eighty seven (69%) had a single level fused, thirty three (26%) had 2 levels fused. Six cases had three or more levels fused. Forty cases had had one or more previous decompressive procedures at the target level. All cases had leg pain due to neurological compression associated with some form of deformity. Fifty three percent had a spondylolisthesis, 20 % had degenerative scoliosis with collapse of the disc space being the most common other deformity. The mean pre operative VAS pain score dropped from 6.95 (sd 2.0) to 3.2 (sd 2.4). (p< 0.0001 paired t test). The mean percentage VAS improvement was 49.7% (95% ci 42.4% to 57.1%). Twenty seven percent achieved greater then 80% pain improvement with 47% achieving greater than 60% pain improvement. The mean LBOS score rose from 21.8 (95% ci 19.6 to 24.0) to 37.9 (95% ci 35.1 to 40.6) (p< 0.001 paired t test). The mean percentage improvement in LBOS was 120.7% (95% ci 94.6% to 146%).
Complications consisted of 3 cases of minor wound drainage that settled, a possible deep infection that settled with antibiotics. There were 4 cases of transient leg weakness that recovered and one case of postoperative extradural heamatoma requiring evacuation for partial cauda equina lesion (near full recovery). Unexplained persistence of leg pain or new leg pain was present 8 cases. Three cases resolved spontaneously , 2 cases were due to screw malposition and required revision and 3 cases required re-exploration for further foraminal decompression. Other medical problems included pulmonary embolus (1), chest infection/atelectasis (2), confusional state (2), paralytic ileus (3), Atrial fibrillation (2), myocardial infarction (1).
Discussion: Posterior lumbar interbody fusion with insert an rotate implants for neural compression gives reasonable pain relief and reduction in disability with a low complication rate for the target (elderly) population.
The abstracts were prepared by Dr Robert Moore. Correspondence should be addressed to him at Spine Society of Australia, c/o the Adelaide Centre for Spinal Research, Institute of Medical and Veterinary Science, PO Box 14, Rundle Mall, Adelaide SA 500, Australia.
