The June 18, 2014 article, “Normal Health-Related Quality of Life and Ability to Work Twenty-nine Years After in Situ Arthrodesis for High-Grade Isthmic Spondylolisthesis” by Joelson et al. reports results that challenge the current approach generally used in treating this pediatric spinal disorder.
Sweden and neighboring Scandanavian countries have been leaders in studying long-term results of treatment for a wide variety of orthopaedic conditions, with an impressive rate of follow-up in this relatively stable population. This article is one more example. Thirty-five of 40 patients were evaluated with physical examination and patient-reported outcome questionnaires at a mean of 29 years and a minimum of 23 years following L4-S1 posterior fusion and L5-S1 anterior fusion for isthmic spondylolisthesis over 50%. Harrington rod spinal instrumentation was used in 15% of the cases, while the others were treated with postoperative casts for 3 months. All patients were reported to have a solid fusion from the initial surgery, and there was no motor function loss. While there was a substantial range of scores in the outcome questionnaires, there was no significant difference in outcomes between the surgical patients and norms for the Swedish population.
Despite the results reported here, this approach to treating high-grade isthmic spondylolisthesis in the pediatric population has largely been replaced with pedicle screw and rod spinal instrumentation from L4 to S1, partial reduction of the slip, and posterior fusion, with anterior L5-S1 fusion added at times. The primary problem with this approach is that there is a reported risk of iatrogenic nerve root injury in 8% to 30% of cases, with resultant weakness or absent function of one or more distal extremity muscles, even if intraoperative neurologic monitoring is used.
The pendulum has essentially fully swung away from the treatment described in this article to the current instrumented approach. The use of post-operative casts with in situ fusion is considered old-fashioned and a treatment thought not acceptable to patients today. However, given the good long-term results reported in this article with in situ fusion and casting, this approach needs to be re-introduced into the pre-operative discussion and be included as a very acceptable surgical option for young patients with high-grade isthmic spondylolisthesis. While we await the long-term follow-up results of patients treated with spinal instrumentation, partial reduction, and fusion as practiced today, avoiding the risk of neurologic deficit in the lower leg will lead some parents to select in situ fusion and casting, with casts generally being tolerated quite well by pediatric patients.