Acta Neurochirurgica

, Volume 151, Issue 5, pp 519–527 | Cite as

Randomized controlled trials in neurosurgery—how good are we?

Neurosurgical Concepts



The strongest evidence in medical clinical literature is represented by randomized controlled trials (RCTs). This study was designed to evaluate neurosurgically relevant RCTs published recently by neurosurgeons.


A literature search in MEDLINE and EMBASE included all clinical studies published up to 30 June 2006. RCTs with neurosurgical relevance published by at least one author with affiliation to a neurosurgical department were selected. The number and characteristics of individual trials were recorded, and the quality of the trials with regard to study design, quality of reporting, and relevance for clinical practice was assessed by two different investigators using a modification of the Scottish Intercollegiate Guidelines Network methodology checklist. Changes of RCT quality over time as well as factors influencing the quality were analyzed.


From the initial search results (MEDLINE n = 3,860, EMBASE n = 3,113 articles), 159 RCTs published by neurosurgeons were extracted for final evaluation. Of the RCTs, 62% have been published since 1995; 52% came from the USA, UK, and Germany. The median RCT sample size was 78 patients and the median follow-up 35.7 weeks. Fifty-two percent of all RCTs were of good, 37% of moderate, and 11% of bad quality, with an improvement over time. RCTs with financial funding and RCTs with a sample size of >78 patients were of significantly better quality. There were no major differences in the rating of the studies between the two investigators.


Only a fraction of neurosurgically relevant literature consists of RCTs, but the quality is satisfying and has significantly improved over the last years. An adequate sample size and sufficient financial support seem to be of substantial importance with regard to the quality of the study. Our data also show that by using a standardized checklist, the quality of trials can be reliably assessed by observers of different experience and educational levels.


Randomized controlled trial Clinical trial Evidence-based medicine Neurosurgery 



  1. 1.
    Curry JI, Reeves B, Stringer MD (2003) Randomized controlled trials in pediatric surgery: could we do better? J Pediatr Surg 38:556–559. doi: 10.1053/jpsu.2003.50121 PubMedCrossRefGoogle Scholar
  2. 2.
    Guyatt GH, Sackett DL, Sinclair JC, Hayward R, Cook DJ, Cook RJ (1995) Users‘ guides to the medical literature IX. A method for grading health care recommendations. Evidence-Based Medicine Working Group. JAMA 274:1800–1804. doi: 10.1001/jama.274.22.1800 PubMedCrossRefGoogle Scholar
  3. 3.
    Haines SJ (1979) Randomized clinical trials in the evaluation of surgical innovation. J Neurosurg 51:5–11PubMedGoogle Scholar
  4. 4.
    Haines SJ (1983) Randomized clinical trials in neurosurgery. Neurosurgery 12:259–264. doi: 10.1097/00006123-198303000-00001 PubMedCrossRefGoogle Scholar
  5. 5.
    Haines SJ (2001) History of randomized clinical trials in neurosurgery. Neurosurg Clin N Am 12:211–216PubMedGoogle Scholar
  6. 6.
    Hill CL, LaValley MP, Felson DT (2002) Secular changes in the quality of published randomized clinical trials in rheumatology. Arthritis Rheum 46:779–784. doi: 10.1002/art.512 PubMedCrossRefGoogle Scholar
  7. 7.
    Johnson AG, Dixon JM (1997) Removing bias in surgical trials. BMJ 314:916–917PubMedGoogle Scholar
  8. 8.
    Kyriakidi M, Ioannidis JP (2002) Design and quality considerations for randomized controlled trials in systemic sclerosis. Arthritis Rheum 47:73–81. doi: 10.1002/art1.10218 PubMedCrossRefGoogle Scholar
  9. 9.
    Majeed AW, Troy G, Nicholl JP, Smythe A, Reed MW, Stoddard CJ, Peacock J, Johnson AG (1996) Randomised, prospective, single-blind comparison of laparoscopic versus small-incision cholecystectomy. Lancet 347:989–994. doi: 10.1016/S0140-6736(96) 90143-9 PubMedCrossRefGoogle Scholar
  10. 10.
    Morris GF, Bullock R, Marshall SB, Marmarou A, Maas A, Marshall LF (1999) Failure of the competitive N-methyl-D-aspartate antagonist Selfotel (CGS 19755) in the treatment of severe head injury: Results of two phase III clinical trials. J Neurosurg 91:737–743PubMedCrossRefGoogle Scholar
  11. 11.
    Ostertag CB (2001) Measuring the importance of scientific results in neurosurgery. Acta Neurochir Suppl (Wien) 78:185–188Google Scholar
  12. 12.
    Penn RD, Savoy SM, Corcos D, Latash M, Gottlieb G, Parke B, Kroin JS (1989) Intrathecal baclofen for severe spinal spasticity. N Engl J Med 320:1517–1521PubMedGoogle Scholar
  13. 13.
    Perl TM, Cullen JJ, Wenzel RP, Zimmerman MB, Pfaller MA, Sheppard D, Twombley J, French PP, Herwaldt LA, Bentler S, Brown K, Bushnell W, Coffman S, Finlay J, Forbes R, Hintemiester M, James C, Helgerson B, Preston A, Swift J (2002) Intranasal mupirocin to prevent postoperative Staphylococcus aureus infections. N Engl J Med 346:1871–1877. doi: 10.1056/NEJMoa003069 PubMedCrossRefGoogle Scholar
  14. 14.
    Richter HP, Kast E, Tomczak R, Besenfelder W, Gaus W (2001) Results of applying ADCON-L gel after lumbar discectomy: the German ADCON-L study. J Neurosurg 95:179–189PubMedGoogle Scholar
  15. 15.
    Scottish Intercollegiate Guidelines Network (SIGN) SIGN 50 (2005) A guideline developers' handbook. Methodology Checklist 2: Randomised Controlled Trials
  16. 16.
    Solomon MJ, Laxamana A, Devore L, McLeod RS (1994) Randomized controlled trials in surgery. Surgery 115:707–712PubMedGoogle Scholar
  17. 17.
    Solomon MJ, McLeod RS (1995) Should we be performing more randomized controlled trials evaluating surgical operations? Surgery 118:459–467. doi: 10.1016/S0039-6060(05) 80359-9 PubMedCrossRefGoogle Scholar
  18. 18.
    Solomon MJ, McLeod RS (1998) Surgery and the randomised controlled trial: past, present and future. Med J Aust 169:380–383PubMedGoogle Scholar
  19. 19.
    Thomas DG, Kitchen ND (1994) Minimally invasive surgery. Neurosurgery. BMJ 308:126–128PubMedGoogle Scholar
  20. 20.
    Troidl H (1998) Conceptional and structural conditions for successful clinical research. Langenbecks Arch Surg 383:306–316. doi: 10.1007/s004230050138 PubMedCrossRefGoogle Scholar
  21. 21.
    Uhl W, Wente MN, Buchler MW (2000) Surgical clinical studies and their practical realization. Chirurg 71:615–625. doi: 10.1007/s001040051113 PubMedCrossRefGoogle Scholar
  22. 22.
    Vranos G, Tatsioni A, Polyzoidis K, Ioannidis JP (2004) Randomized trials of neurosurgical interventions: a systematic appraisal. Neurosurgery 55:18–25. doi: 10.1227/01.NEU.0000126873.00845.A7 PubMedCrossRefGoogle Scholar
  23. 23.
    Winkler JT (1987) The academic celebrity sndrome. Lancet 21:450. doi: 10.1016/S0140-6736(87) 90151-6 CrossRefGoogle Scholar
  24. 24.
    Wyler AR, Hermann BP, Somes G (1995) Extent of medial temporal resection on outcome from anterior temporal lobectomy: a randomized prospective study. Neurosurgery 37:982–990PubMedCrossRefGoogle Scholar

Copyright information

© Springer-Verlag 2009

Authors and Affiliations

  1. 1.Department of NeurosurgeryUniversity of Munich Medical Center–Grosshadern, Ludwig-Maximilians-UniversityMunichGermany
  2. 2.Department of NeurosurgeryUniversity of Munich Medical CenterMunichGermany

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