Minimally invasive tethered cord release in adults: A comparison of open and mini-open approaches

Object. Symptomatic tethered cord and associated anomalies such as diastematomyelia rarely present during adulthood but can cause significant pain as well as motor, sensory, and bladder dysfunction. As with children, studies have shown that surgical detethering may provide improvement in pain and neurological deficits. Typical surgical management involves an open laminectomy, sectioning of the filum terminale, and exploration of the split cord malformation. Such open approaches, however, cause significant paraspinous muscle trauma and scarring. Recent advances in minimally invasive techniques allow for access to the spine and thecal sac while minimizing associated muscular trauma. The authors present a comparison of open versus minimally invasive surgery to treat adult tethered cord syndrome. Methods. Six adult patients underwent surgical release of a tethered spinal cord (2 of them also had diastematomyelia). The mean age of the patients was 47.78 years (range 31-64 years). All medical records and images were retrospectively reviewed. Three of the patients underwent traditional open laminectomies for detethering (open group) while the other 3 patients underwent minimally invasive (mini-open) spinal cord detethering. The length of the incision, length of stay, estimated blood loss, and complications were compared between the 2 groups. Results. All 6 patients had tethered spinal cords, and 1 patient in each group had diastematomyelia. The mean estimated blood loss during surgery (300 ml in the open group vs 167 ml in the mini-open group, p = 0.313) and the mean length of stay (7 days in the open group vs 6.3 days in the mini-open group, p = 0.718) were similar between the 2 groups. The incision length was half as long in the mini-open group versus the open group. However, 1 patient in the mini-open group developed a postoperative pseudomeningocele requiring surgical revision, whereas the open group had no revision surgeries. Conclusions. Cases of symptomatic diastematomyelia and tethered cord in adults can be safely and effectively explored through a mini-open approach. In this small case series, the authors did find that the mini-open group had an incision that was 50% smaller than the open group, but they did not find a significant clinical difference between the groups.