Surgical Outcomes of Low-dysplastic Isthmic Spondylolisthesis Treated with PLIF and Total Facetectomy
Introduction: Isthmic spondylolisthesis can cause spinal instability and radicular pain due to neuroforaminal compression. Surgical treatment often necessitates slip reduction and disc height restoration. While slip reduction provides a larger area for arthrodesis, surgical reduction may cause neurological deficits and/or instrumentation failure. The authors report the subject is controversial.
Purpose: This study investigated surgical outcomes of posterior lumbar interbody fusion (PLIF) with total facetectomy to treat low-dysplastic isthmic spondylolisthesis (LDIS), the effects of slip reduction on outcomes, and proper slip reduction.
Methods: This retrospective study involved 106 patients (36 women, 70 men) who underwent PLIF with total facetectomy for LDIS between the years 1996 and 2010. Surgical indications included disabling radicular pain with or without low back pain unresponsive to typical nonoperative treatments. Average age was 57 years. The 106 patients were followed for at least 2 years following surgery.
Clinical assessments were performed before surgery and at 1, 6, 12, 18 and 24 months postoperative, followed by annual evaluations. The Japanese Orthopaedic Association (JOA) scoring system was utilized to evaluate clinical outcomes. The Hirabayashi method was used to analyze recovery rate.
At each clinical assessment, plain lateral radiographs were obtained and used to measure slip value and disc height. Slip reduction was measured by comparing the pre- and immediate postoperative lateral x-rays. Three surgeons, blinded to the clinical results, performed disc height and slip measurements. Furthermore, fusion and nonunion were examined.
Results: Preoperative JOA score was 14 points (3-25) and postoperative 25 points (11-29). Average rate of recovery was 73%, and surgical outcomes were excellent in 60% (n=64), good in 23% (n=24), fair in 10% (n=11), and poor in 7% (n=7) of patients. The pre- and postoperative slip values and disc height measures are shown in Table 1.
Postoperative complications included neurological deficits (7%, n=7), instrument failure (7%, n=7), adjacent segment degeneration (5%, n=5), and pseudoarthrosis (4%, n=4).
Conclusion: In this study, PLIF with total facetectomy to treat LDIS demonstrated good outcomes.
Okuda S, Oda T, Yamasaki R, Haku T, Maeno T, Iwasaki M. Posterior Lumbar Interbody Fusion with Total Facetectomy for Low-dysplastic Isthmic Spondylolisthesis: Effects of Slip Reduction on Surgical Outcomes. J Neurosurg Spine. 2014;21:171-178.
This retrospective study attempts to answer two main questions:
- How good are the outcomes for patients who undergo PLIF treatment for isthmic spondylolisthesis?
- Does slip reduction influence clinical outcomes? If so, what is an appropriate slip reduction?
The authors make the point that slip reduction is desirable since pseudoarthrosis rates are reduced with slip reduction. They also indicated that total facetectomy allowed for lower rates of neurologic deficit, better slip reduction and high union rate. No correlation was seen between adjacent segment degeneration, slip reduction and disc height restoration.
From this paper, it seems that patients experienced satisfactory clinical outcomes if slip reduction was less than 20%. Patients with greater slip reductions had poor outcomes. It is possible total facetectomy helped to avoid neurologic injuries, since there were no posterior elements to compress the neural structures when the reduction is performed.