Clinical Research: Spine Surgery
Selected Abstracts 2008-2009
Todd J. Albert, MD
Alexander R. Vaccaro, MD
Alan S. Hilibrand, MD
D. Greg Anderson, MD
Ravi K. Ponnappan, MD
Jeffrey A. Rihn, MD
Surgical versus nonsurgical therapy for lumbar spinal stenosis.
Weinstein JN, Tosteson TD, Lurie JD, Tosteson AN, Blood E, Hanscom B, Herkowitz H, Cammisa F, Albert T, Boden SD, Hilibrand A, Goldberg H, Berven S, An H; SPORT Investigators.
N Engl J Med. 2008 Feb 21;358(8):794-810.
BACKGROUND: Surgery for spinal stenosis is widely performed, but its effectiveness as compared with nonsurgical treatment has not been shown in controlled trials.
METHODS: Surgical candidates with a history of at least 12 weeks of symptoms and spinal stenosis without spondylolisthesis (as confirmed on imaging) were enrolled in either a randomized cohort or an observational cohort at 13 U.S. spine clinics. Treatment was decompressive surgery or usual nonsurgical care. The primary outcomes were measures of bodily pain and physical function on the Medical Outcomes Study 36-item Short-Form General Health Survey (SF-36) and the modified Oswestry Disability Index at 6 weeks, 3 months, 6 months, and 1 and 2 years.
RESULTS: A total of 289 patients were enrolled in the randomized cohort, and 365 patients were enrolled in the observational cohort. At 2 years, 67% of patients who were randomly assigned to surgery had undergone surgery, whereas 43% of those who were randomly assigned to receive nonsurgical care had also undergone surgery. Despite the high level of nonadherence, the intention-to-treat analysis of the randomized cohort showed a significant treatment effect favoring surgery on the SF-36 scale for bodily pain, with a mean difference in change from baseline of 7.8 (95% confidence interval, 1.5 to 14.1); however, there was no significant difference in scores on physical function or on the Oswestry Disability Index. The as-treated analysis, which combined both cohorts and was adjusted for potential confounders, showed a significant advantage for surgery by 3 months for all primary outcomes; these changes remained significant at 2 years.
CONCLUSIONS: In the combined as-treated analysis, patients who underwent surgery showed significantly more improvement in all primary outcomes than did patients who were treated nonsurgically.
Revision strategies in lumbar total disc arthroplasty.
Patel AA, Brodke DS, Pimenta L, Bono CM, Hilibrand AS, Harrop JS, Riew KD, Youssef JA, Vaccaro AR.
Spine. 2008 May 15;33(11):1276-83.
STUDY DESIGN: Review of Literature. OBJECTIVE: To review the published literature regarding revision lumbar total disc arthroplasty as well as potential options to avoid complications associated with the revision surgical approach.
SUMMARY OF BACKGROUND DATA: The use of lumbar total disc arthroplasty in the United States has not achieved the same popularity as seen in Europe, where studies have reported favorable short- and intermediate-term results. In the United States, despite recognition that disc replacement may reduce the incidence of adjacent segment disease, the risk of potential complications associated with primary and revision total disc arthroplasty have diminished surgeon enthusiasm for the procedure. The use of adhesion barriers may address some of these concerns.
METHODS: A series of Ovid Medline and Pubmed-National Library of Medicine/National Institutes of Health (www.ncbi.nlm.nih.gov) searches were performed. Only articles written in English journals or published with English translations were included. Level of evidence of the selected articles was assessed.
RESULTS: The need for revision of lumbar total disc arthroplasty has been reported in a number of prospective, randomized trials (level I or II evidence). Suboptimal patient selection and/or surgical technique accounted for the majority of failed disc arthroplasties. Revision procedures have included posterior stabilization or anterior explantation with revision to arthroplasty or conversion to arthrodesis. The risk of injury to the great vessels and retroperitoneal structures is greater during revision than primary procedures. The use of a far lateral, or transpsoas approach to the anterior column may reduce these adverse events. The use of adhesion barriers has been shown to reduce adhesions in abdominal and pelvic surgery and may be of benefit in revision disc arthroplasty.
CONCLUSION: Adherence to stringent indications and meticulous surgical technique may reduce the number of revision procedures. Further, the use of barriers to adhesion formation during the primary arthroplasty may also reduce risk to the retroperitoneal structures during revision approaches.
Lumbar adjacent segment degeneration and disease after arthrodesis and total disc arthroplasty.
Harrop JS, Youssef JA, Maltenfort M, Vorwald P, Jabbour P, Bono CM, Goldfarb N, Vaccaro AR, Hilibrand AS.
Spine. 2008 Jul 1;33(15):1701-7.
STUDY DESIGN: Systematic review of published incidence of radiographic adjacent segment degeneration (ASDeg) and symptomatic adjacent segment disease (ASDis) after arthrodesis or total disc replacement.
OBJECTIVE: Assess impact of surgery method and other factors on the incidence of ASDeg and ASDis.
SUMMARY OF BACKGROUND DATA: Twenty-seven articles, none of which were class I or II, met the inclusion criteria. Twenty involved arthrodesis (1732 patients) and 7 involved arthroplasty (758 patients). Nineteen detailed ASDeg and 16 detailed ASDis.
METHODS: Data were established for number of patients, gender, average patient age, incidence of ASDeg and ASDis, average time to follow-up, and level and type of surgery. Multivariate logistic regression was used to identify which parameters had a significant effect on the incidence of ASDeg and ASDis.
RESULTS: Three hundred fourteen of 926 patients in the arthrodesis group (34%) and 31 out of 313 patients in the total disc replacement group (9%) developed ASDeg. (P < 0.0001) Multivariate logistic regression indicated that higher odds of ASDeg were associated with: older patients (P < 0.001); arthodesis (P = 0.0008); and longer follow-up (P = 0.0025). For ASDis, 173/1216 (14%) arthrodesis patients developed ASDis compared to 7/595 (1%) of arthroplasty patients (P < 0.0001). Using multivariate logistic regression, higher odds of ASDis were seen in studies with fusion (P < 0.0001), higher percentages of male patients (P = 0.0019), and shorter follow-up (P < 0.05).
CONCLUSION: Analysis of the literature suggests a correlation between fusion and the development of ASDeg compared to arthroplasty, but this association is dampened by the influence of patient age. There is a stronger correlation between fusion and ASDis compared to arthroplasty. The data supports only a class C recommendation (lowest tier) for the use of arthroplasty to reduce ASDis and disc degeneration compared to arthrodesis.