Previously, Chad A. Krueger, MD, JBJS Deputy Editor for Social Media, selected what he deemed to be the most clinically compelling findings from among the more than 25 studies cited in the June 20, 2018 Specialty Update on Spine Surgery. In this OrthoBuzz post, Theodore J. Choma, MD, author of the Specialty Update on Spine Surgery, selected his “top five.”
–A registry study of 765 patients with adult isthmic spondylolisthesis and at least 2 years of post-treatment outcome data found that at 1 year, global-assessment improvements were reported in 54% of patients who underwent uninstrumented posterolateral fusion, 68% of patients who underwent instrumented posterolateral fusion, and 70% of patients who underwent interbody fusion. Although similar patterns were seen in VAS back pain scores and in 2-year data, fusion with instrumentation was associated with a higher risk of reoperation.
Acute Low Back Pain
–In a cost analysis using data from a previously published Level-II study that randomized 220 patients with acute low back pain to early physical therapy or usual (delayed-referral) care, authors concluded that the incremental cost of early PT was $32,058 per quality-adjusted life year and that early PT is therefore cost-effective.1
Metabolic Bone Disease
–A randomized trial of 66 women ≥50 years of age who had osteoporosis and had undergone lumbar interbody arthrodesis found that those who received once-weekly teriparatide for 6 months following surgery demonstrated higher fusion rates than those in the control cohort (69% versus 35%). Once weekly teriparatide may be worth considering to improve fusion rates in this challenging patient population.
Adult Deformity Correction
–To test the hypothesis that performing 3-column osteotomies more caudally in the lumbar spine might improve sagittal malalignment correction, authors analyzed 468 patients from a spine deformity database who underwent 3-column osteotomies.2 The mean resection angle was 25.1° and did not vary by osteotomy level. No variations were found in the amount of sagittal vertical axis or pelvic tilt correction, but lower-level osteotomies were associated with more frequent pseudarthroses and postoperative motor deficits.
Spinal Cord Injury
–Authors directly measured the mean arterial pressure and cerebrospinal fluid pressure in 92 consecutive patients with traumatic spinal cord injury. Using that data to indirectly monitor the patients’ spinal cord perfusion pressure,3 the authors found that patients who experienced more episodes of spinal cord perfusion pressures <50 mm Hg were less likely to manifest objective improvements in spinal cord function.
- Fritz JM, Kim M, Magel JS, Asche CV. Cost-effectiveness of primary care management with or without early physical therapy for acute low back pain: economic evaluation of a randomized clinical trial. Spine (Phila Pa 1976).2017 Mar;42(5):285-90.
- Ferrero E, Liabaud B, Henry JK, Ames CP, Kebaish K, Mundis GM, Hostin R, Gupta MC, Boachie-Adjei O,Smith JS, Hart RA, Obeid I, Diebo BG, Schwab FJ, Lafage V. Sagittal alignment and complications following lumbar 3-column osteotomy: does the level of resection matter?J Neurosurg Spine. 2017 Nov;27(5):560-9. Epub 2017 Sep 8.
- Squair JW, Bélanger LM, Tsang A, Ritchie L, Mac-Thiong JM, Parent S, Christie S, Bailey C, Dhall S, Street J,Ailon T, Paquette S, Dea N, Fisher CG, Dvorak MF, West CR, Kwon BK. Spinal cord perfusion pressure predicts neurologic recovery in acute spinal cord injury. 2017 Oct 17;89(16):1660-7. Epub 2017 Sep 15.
Every month, JBJS publishes a Specialty Update—a review of the most pertinent and impactful studies published in the orthopaedic literature during the previous year in 13 subspecialties. Click here for a collection of all OrthoBuzz Specialty Update summaries.
This month, OrthoBuzz asked Theodore Choma, MD, co-author of the June 21, 2017 Specialty Update on spine surgery, to select the five most clinically compelling findings from among the more than 40 studies cited in the article.
Biomaterials and Biologics
A multicenter randomized prospective trial compared osteogenic protein-1 (OP-1, also known as bone morphogenetic protein [BMP]-7) combined with local autograft to iliac crest autograft combined with local autograft in posterolateral lumbar fusion. Based on computed tomography (CT) scan assessments, the authors found a 54% fusion rate in the OP-1 group and a 74% fusion rate in the iliac crest group. OP-1 appears to be a poor substitute for iliac crest autograft for achieving posterolateral lumbar fusion.
Adult Spinal Deformity (ASD)
We continue to elucidate the risks and morbidity of adult degenerative spinal deformity surgery. The Scoli-Risk-1 study,1 a Level-III multicenter, prospective observational study, reported on 272 patients with ASD treated surgically. Twenty-two percent of the patients were discharged from the hospital with a decline in the lower-extremity motor score, while only 13% demonstrated improvement. However, by 6 months postoperatively, 21% demonstrated improvement, 69% demonstrated maintenance, and 11% continued to demonstrate lower-extremity motor decline.
Spinal Cord Injury
A Level-I, randomized, crossover trial2 examined whether the character of neuropathic pain following spinal cord injury determined the response to 300 mg/day of either pregabalin or oxcarbazepine. Both anticonvulsant medications significantly improved neuropathic pain in these patients. A subgroup analysis demonstrated that oxcarbazepine was more effective in patients without evoked pain and pregabalin was more effective in patients with evoked pain.
Lumbar Degenerative Spondylolisthesis
To address the consequences of fusion along with decompression in degenerative lumbar spondylolisthesis, a Level-I, randomized controlled trial3 specifically compared laminectomy only with laminectomy plus fusion among 66 patients with stable degenerative spondylolisthesis and symptomatic lumbar stenosis. Patients in the fusion group had significantly higher SF-36 scores at 2, 3, and 4 years, but the groups did not differ with respect to ODI scores at 2 years. The authors reported a significantly higher reoperation rate (34% compared with 14%) in the decompression-only group over the 4-year follow-up, but patients who underwent decompression with fusion began to have an increase in the probability of reoperation 36 months after surgery.
We have more evidence of the effectiveness of vertebral cement augmentation for osteoporotic thoracolumbar compression fractures. The authors of a level-I systematic review and meta-analysis examined randomized controlled trials comparing vertebroplasty with conservative treatment or placebo/sham and identified 11 relevant studies involving 1,048 subjects. The meta-analysis found that patients receiving percutaneous vertebroplasty (n = 531) had lower pain ratings at 1 to 2 weeks, 2 to 3 months, and 1 year. The effect size of vertebroplasty was significant and close to the minimal clinically important difference (MCID).
- Lenke LG, Fehlings MG, Shaffrey CI, Cheung KM, Carreon L, Dekutoski MB, Schwab FJ, Boachie-Adjei O, Kebaish KM, Ames CP, Qiu Y, Matsuyama Y, Dahl BT, Mehdian H, Pellis´e-Urquiza F, Lewis SJ, Berven SH. Neurologic outcomes of complex adult spinal deformity surgery: results of the prospective, multicenter Scoli-RISK- 1 study. Spine (Phila Pa 1976). 2016 Feb;41(3):204-12.
- Min K, Oh Y, Lee SH, Ryu JS. Symptom-based treatment of neuropathic pain in spinal cord-injured patients: a randomized crossover clinical trial. Am J Phys Med Rehabil. 2016 ;95(5):330–8
- Ghogawala Z, Dziura J, Butler WE, Dai F, Terrin N, Magge SN, Coumans JV, Harrington JF, Amin-Hanjani S, Schwartz JS, Sonntag VK, Barker FG 2nd, Benzel EC. Laminectomy plus fusion versus laminectomy alone for lumbar spondylolisthesis. N Engl J Med. 2016 Apr 14;374(15):1424-34.
OrthoBuzz occasionally receives posts from guest bloggers. This guest post comes from Brett A. Freedman, MD, in response to two recent NEJM studies on treating spondylolisthesis.
The April 14, 2016 edition of The New England Journal of Medicine published results from two randomized clinical trials (RCTs) evaluating the benefits of laminectomy alone versus laminectomy and fusion for the treatment of specific spinal conditions in patients 50 to 80 years old, with at least 2-year follow-up. The larger study was conducted in Sweden and included 247 patients, 135 of whom had degenerative spondylolisthesis of some magnitude. In this study, the surgical technique varied and was left to the treating provider’s preference. The ultimate conclusion of this study was that adding fusion to the procedure did not result in better patient outcomes by any index measured.
Conversely, an essentially concurrent but unrelated RCT evaluating similar outcomes in a US patient population (n=66) with degenerative spondylolisthesis that measured at least 3 mm, but in which there was no instability, concluded that spinal fusion, using a standardized technique (pedicle screws and rods with iliac crest bone graft), did provide a significant clinical benefit. Specifically, this study found significant improvement in SF-36 physical-component summary scores (the primary outcome measure) and lower reoperation rates (14% vs. 34%; p=0.05) compared to decompression alone.
When two Level 1 studies published on the same day in the same high-impact journal come to divergent conclusions about the same clinical question, we must pause and look to the past. Spine surgeons have investigated decompression alone for spondylolisthesis, first by necessity (prior to the era of reliable spinal fusion) and then later in comparison to in-situ and instrumented fusion1,2. Consensus is consistent with anatomic reasoning. Dysfunctional lumbar mobile segments, especially those with preserved or excessive motion (i.e. >2 to 4 mm change on flexion-extension films), produce a mechanical pathoanatomic sequence of events that leads to critical and clinically symptomatic spinal stenosis. Addressing this first cause is paramount.
The immediate effect of surgery type is largely neutralized by the fact that the decompression component, which is common to both approaches, is principally responsible for acute improvement. Because most prospective studies are not able to reliably track patients beyond 2 to 5 years, the longer-term benefits of a solid arthrodesis of a dysfunctional spinal-motion segment compared to a simple decompression in which some of the incompetent posterior elements are further surgically removed remain largely unknown. Anecdotally, spine surgeons recognize that failures of decompression alone in mobile spondylolisthesis occur quite frequently—and that revision fusion surgery in this situation is significantly more complicated than primary decompression and fusion. That was the case in the Swedish study, where the majority of revision surgeries in the decompression-only cohort were performed at the same level as the prior surgery, versus adjacent levels in the fusion group. And, again, reoperation rates were significantly higher (>2x) in the decompression-only group in the US study.
Given conflicting data3, there likely are cofactors that need to be identified and further studied to select cases of spondylolisthesis that can be treated well with decompression alone, versus those that require the stabilizing effect of a fusion. Until then, surgeons must weigh the data available and provide the surgical option they feel is best for each individual patient.
Brett A. Freedman, MD is an orthopaedic surgeon specializing in spine trauma and degenerative spinal diseases at the Mayo Clinic in Rochester, MN
- Fischgrund JS, Mackay M, Herkowitz HN, Brower R, Montgomery DM, Kurz LT. Degenerative lumbar spondylolisthesis with spinal stenosis: a prospective, randomized study comparing decompressive laminectomy and arthrodesis with and without spinal instrumentation. Spine (Phila Pa 1976). 1997 Dec 15;22(24):2807-12.
- Bridwell KH, Sedgewick TA, O’Brien MF, Lenke LG, Baldus C. The role of fusion and instrumentation in the treatment of degenerative spondylolisthesis with spinal stenosis. J Spinal Disord. 1993 Dec;6(6):461-72.
- Joaquim AF, Milano JB, Ghizoni E, Patel AA. Is There a Role for Decompression Alone for Treating Symptomatic Degenerative Lumbar Spondylolisthesis?: A Systematic Review. J Spinal Disord Tech. 2015 Dec 24. [Epub ahead of print]
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.