Journal of Neurosurgery: Spine
Robert E. Isaacs, Vinod K. Podichetty, Paul Santiago, Faheem A. Sandhu, John Spears, Kevin Kelly, Laurie Rice and Richard G. Fessler
The authors have developed a novel technique for percutaneous fusion in which standard microendoscopic discectomy is modified. Based on data obtained in their cadaveric studies they considered that this minimally invasive interbody fusion could be safely implemented clinically. The authors describe their initial experience with a microendoscopic transforaminal lumbar interbody fusion (METLIF) technique, with regard to safety in the placement of percutaneous instrumentation, perioperative morbidity, and early postoperative results.
The METLIF procedure was performed unilaterally in 20 patients with single-level lumbar spondylolisthesis or pure mechanical back pain with endoscopic assistance, hemilaminectomy, unilateral facetectomy, and microdiscectomy. Two interbody grafts were placed via the lateral exposure of the disc space. Bilateral percutaneous pedicle screws were then inserted.
Compared with patients who had undergone single-level posterior LIF at the same institutions, intraoperative blood loss, hospital length of stay (LOS), and postoperative narcotic agent use were significantly lower in the METLIF group. The mean LOS for the percutaneous fusion group was 3.4 days (5.1 days in those who underwent PLIF; p < 0.02). There have been no procedure-related complications in this series to date.
The METLIF technique provided an option for percutaneous interbody fusion similar to that in open surgery while minimizing destruction to adjacent tissues. This technique was safe and exhibited a trend toward decreased intraoperative blood loss, postoperative pain, total narcotic use, and the risk of transfusion.
Mohamad Bydon, Risheng Xu, David Santiago-Dieppa, Mohamed Macki, Daniel M. Sciubba, Jean-Paul Wolinsky, Ali Bydon, Ziya L. Gokaslan and Timothy F. Witham
The aim of this study was to study the long-term outcomes of patients undergoing instrumented posterior fusion of the lumbar spine.
The authors present 511 patients who underwent instrumented arthrodesis for lumbar degenerative disease over a 23-year period at a single institution. Patients underwent follow-up for an average of 39.73 ± 46.52 months (± SD) after the index lumbar arthrodesis procedure.
The average patient age was 59.45 ± 13.48 years. Of the 511 patients, 502 (98.24%) presented with back pain, 379 (74.17%) with radiculopathy, 76 (14.87%) with motor weakness, and 32 (6.26%) with preoperative bowel/bladder dysfunction. An average of 2.04 ± 1.03 spinal levels were fused. Postoperatively, patients experienced a significant improvement in back pain (p < 0.0001) and radiculopathy (p < 0.0001). Patients with fusions excluding the sacrum (floating fusions) were statistically more likely to develop adjacent-segment disease (ASD) than those with fusion constructs ending at S-1 distally (p = 0.030) but were less likely to develop postoperative radiculopathy (p = 0.030). In the floating fusion cohort, 31 (12.11%) of 256 patients had cephalad ASD, whereas 39 (15.29%) of 255 patients in the lumbosacral cohort had cephalad ASD development; this was not statistically different (p = 0.295). This suggests that caudad ASD development in the floating fusion cohort is due to the added risk of an unfused L5–S1 vertebral level. Because of the elevated risk of symptomatic radiculopathy but lower risk of ASD, patients in the lumbosacral fusion cohort had a reoperation rate similar to those undergoing floating fusions (p = 0.769).
In this paper, the authors present one of the largest cohorts in the Western literature of patients undergoing instrumented fusion for degenerative lumbar spine disease. Patients who had floating lumbar fusions were statistically more likely to develop ASD over time than those who had lumbosacral fusions incorporating the S-1 spinal segment, but were less likely to experience postoperative radicular symptoms. Additional prospective studies may more clearly delineate the long-term risks of instrumented posterolateral fusions of the lumbar spine.
Kaisorn L. Chaichana, Mohamad Bydon, David R. Santiago-Dieppa, Lee Hwang, Gregory McLoughlin, Daniel M. Sciubba, Jean-Paul Wolinsky, Ali Bydon, Ziya L. Gokaslan and Timothy Witham
Posterior lumbar spinal fusion for degenerative spine disease is a common procedure, and its use is increasing annually. The rate of infection, as well as the factors associated with an increased risk of infection, remains unclear for this patient population. A better understanding of these features may help guide treatment strategies aimed at minimizing infection for this relatively common procedure. The authors' goals were therefore to ascertain the incidence of postoperative spinal infections and identify factors associated with postoperative spinal infections.
Data obtained in adult patients who underwent instrumented posterior lumbar fusion for degenerative spine disease between 1993 and 2010 were retrospectively reviewed. Stepwise multivariate proportional hazards regression analysis was used to identify factors associated with infection. Variables with p < 0.05 were considered statistically significant.
During the study period, 817 consecutive patients underwent lumbar fusion for degenerative spine disease, and 37 patients (4.5%) developed postoperative spine infection at a median of 0.6 months (IQR 0.3–0.9). The factors independently associated with an increased risk of infection were increasing age (RR 1.004 [95% CI 1.001–1.009], p = 0.049), diabetes (RR 5.583 [95% CI 1.322–19.737], p = 0.02), obesity (RR 6.216 [95% CI 1.832–9.338], p = 0.005), previous spine surgery (RR 2.994 [95% CI 1.263–9.346], p = 0.009), and increasing duration of hospital stay (RR 1.155 [95% CI 1.076–1.230], p = 0.003). Of the 37 patients in whom infection developed, 21 (57%) required operative intervention but only 3 (8%) required instrumentation removal as part of their infection management.
This study identifies that several factors—older age, diabetes, obesity, prior spine surgery, and length of hospital stay—were each independently associated with an increased risk of developing infection among patients undergoing instrumented lumbar fusion for degenerative spine disease. The overwhelming majority of these patients were treated effectively without hardware removal.