Complete Reduction And Plif Using An Insert & Rotate Technique For Spondylolisthesis
A Review Of 35 Patients
By William Sears, F.R.A.C.S. Sydney NeuroSpine Clinic, Sydney, Australia
Since Briggs and Milligan first described posterior lumbar interbody fusion (PLIF) in 1944, it has been a controversial procedure. Inconsistent results with early techniques and reported high rates of complications resulted in relatively few surgeons adopting PLIF surgery, especially in Australia and New Zealand. While modern pedicle screw instrumentation and the development of intervertebral spreaders and implants have provided a powerful technique for the restoration of spinal balance in degenerative deformity, the debate regarding safety and efficacy has persisted.
At the Spine Society of Australia scientific meeting last year, the author reported on his clinical results in 350 patients managed with PLIF using a distraction/reduction technique and interbody fusion spacers implanted by an Insert and Rotate method. He found high levels of patient satisfaction (of the patients surveyed, 123/131 or 94% considered the surgery worthwhile and 88% said that they would have it again, if necessary) and the incidence of good and excellent rates was 86% in non-compensation patients who underwent surgery for conditions associated with deformity, following the introduction of interbody serrated spacers and additional posterior grafting. The study however, was fairly criticised as being retrospective in nature.
The current study examines prospectively the functional outcomes and safety in a smaller series of patients undergoing complete reduction and PLIF for lumbosacral spondylolisthesis using the distraction/reduction technique and Insert and Rotate interbody fusion spacers.
Methods
A prospective, non-randomized, observational study of 35 patients with lumbosacral degenerative or isthmic spondylolisthesis, operated upon between April 2001 and June 2002.
All patients underwent decompressive laminectomy followed by complete reduction of the spondylolisthetic deformity with the aid of intervertebral disc space spreaders and pedicle screw instrumentation (Figure 1). Wedge-shaped spacers made from Carbon Fiber, Titanium mesh or PEEK plastic were then inserted on their sides and rotated 90 degrees to support the vertebral endplates (Figure 2). Bone graft was then placed beside them, within the disc space and over the partially decorticated residual posterior elements.
Outcomes were measured pre- and postoperatively using the Low Back Outcome Score (LBOS), SF-12, visual analogue pain scores (VAS) and patient satisfaction survey.
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Figure 1: 79 Year Old Female With Degenerative Spondylolisthesis And Lateral Recess Stenosis | |
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Figure 2: Spacers To Support Vertical Endplates | |
Results
Of the 35 patients, 24 had degenerative spondylolisthesis and 11 were isthmic in type. 26 were Meyerding Grade I, seven were Grade II, one was Grade III and one was Grade IV.
The indications for surgery included relief of foraminal stenosis in 26 and likely post decompressive laminectomy instability in 24. There were no compensation patients. Follow-up data was available on 33 of the 35 patients at 6 months (94%) and 14 of the possible 19 patients at 12 months (74%). One patient died of unrelated causes after the 6 month follow-up.
Mean preoperative VAS and LBOS were 5.1 ± 2.5 and 26.5 ± 16.9, respectively. Mean follow-up scores were 2.3 ± 2.3 and 45.7 ± 16.4 at 6 months and 2.3 ± 2.2 and 45.2 ± 19.3 at 12 months (p0.01 for both measures at 6 and 12 months, paired TTest) SF12 scores also improved significantly at 6 and 12 month follow-up (Figure 3 Below).
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Figure 3: Outcome Measures |
At last follow-up, 30 of the 33 patients (with a 6 month follow-up) or 88% described their outcome as good or excellent. No patient reported himself or herself worse off, although one patient had substantially worse outcome measures at her 6 month follow-up (Figure 4). 32 or 97% said the procedure had been worthwhile and 31 or 94% said they would have it again under similar circumstances.
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Figure 4: Patient Assessed Subjected Outcomes |
There were no perioperative deaths. One patient died of unrelated causes subsequent to his 6 month follow-up. There were no interbody implant / PLIF related problems, but there were five intraoperative problems related to pedicle screw placement with one screw loosening during slip reduction, requiring replacement. Average intra- operative blood loss was 810mls. Post-operatively, 3 patients developed an ileus. One patient developed a probable wound infection with high fever which resolved on antibiotics.
DiscussionThis series represents a recent subset of a much larger total series managed with this technique for symptoms associated with spondylolisthetic deformity (193 patients to date). The author has previously reported to the society on the clinical results of the technique but without the benefit of prospective preoperative data. This smaller series appears to confirm the results of the earlier studies and suggests that PLIF using an Insert and Rotate technique can yield satisfactory clinical outcomes with high patient satisfaction and low levels of complications. |
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