- Department of Neurosurgery, University of Baghdad, College of Medicine, Al Risafa, Baghdad, Iraq,
- Department of Neurosurgery, School of Medicine, Royal College of Surgeons in Ireland - Bahrain, Busaiteen, Bahrain,
- Department of Neurosurgery, Sulaiman Al Rajhi University, College of Medicine, Al Bukayriyah, Saudi Arabia,
- Department of Neurosurgery, Al_Iraqia University, College of Medicine, Al Risafa, Baghdad, Iraq,
- Department of Neurosugery, Prince Sattam Bin Abdulaziz University, College of Medicine, Al Kharj - Riyadh, Saudi Arabia,
- Department of Neurosurgery, University of Wisconsin-Madison, Wisconsin, United States
- Department of Neurosurgery, University of Cincinnati, Cincinnati, Ohio, United States.
Samer S. Hoz, Department of Neurosurgery, University of Cincinnati, Cincinnati, Ohio, United States.
DOI:10.25259/SNI_949_2022Copyright: © 2023 Surgical Neurology International This is an open-access article distributed under the terms of the Creative Commons Attribution-Non Commercial-Share Alike 4.0 License, which allows others to remix, transform, and build upon the work non-commercially, as long as the author is credited and the new creations are licensed under the identical terms.
How to cite this article: Hagar A. Algburi1, Mustafa Ismail1, Saad I. Mallah2, Linah S. Alduraibi3, Sama Albairmani4, Aanab O. Abdulameer1, Abdulaziz Saad Alayyaf5, Zaid Aljuboori6, Norberto Andaluz7, Samer S. Hoz7. Outcome measures in neurosurgery: Is a unified approach better? A literature review. 17-Feb-2023;14:61
How to cite this URL: Hagar A. Algburi1, Mustafa Ismail1, Saad I. Mallah2, Linah S. Alduraibi3, Sama Albairmani4, Aanab O. Abdulameer1, Abdulaziz Saad Alayyaf5, Zaid Aljuboori6, Norberto Andaluz7, Samer S. Hoz7. Outcome measures in neurosurgery: Is a unified approach better? A literature review. 17-Feb-2023;14:61. Available from: https://surgicalneurologyint.com/surgicalint-articles/12154/
Background: Accurate assessment and evaluation of health interventions are crucial to evidence-based care. The use of outcome measures in neurosurgery grew with the introduction of the Glasgow Coma Scale. Since then, various outcome measures have appeared, some of which are disease-specific and others more generally. This article aims to address the most widely used outcome measures in three major neurosurgery subspecialties, “vascular, traumatic, and oncologic,” focusing on the potential, advantages, and drawbacks of a unified approach to these outcome measures.
Methods: A literature review search was conducted by using PubMed MEDLINE and Google scholar Databases. Data for the three most common outcome measures, The Modified Rankin Scale (mRS), The Glasgow Outcome Scale (GOS), and The Karnofsky Performance Scale (KPS), were extracted and analyzed.
Results: The original objective of establishing a standardized, common language for the accurate categorization, quantification, and evaluation of patients’ outcomes has been eroded. The KPS, in particular, may provide a common ground for initiating a unified approach to outcome measures. With clinical testing and modification, it may offer a simple, internationally standardized approach to outcome measures in neurosurgery and elsewhere. Based on our analysis, Karnofsky’s Performance Scale may provide a basis of reaching a unified global outcome measure.
Conclusion: Outcome measures in neurosurgery, including mRS, GOS, and KPS, are widely utilized assessment tools for patients’ outcomes in various neurosurgical specialties. A unified global measure may offer solutions with ease of use and application; however, there are limitations.
Keywords: Oncologic neurosurgery, Outcome measures, Traumatic neurosurgery, Unified scale, Vascular neurosurgery
The accurate assessment and evaluation of health interventions are a crucial component of evidence-based care.[
The use of outcome measures in neurosurgery grew in popularity in 1974 with the introduction of the Glasgow Coma Scale. Since then, various outcome measures have appeared, some of which are disease specific — such as the subarachnoid hemorrhage outcome tool — while others are used more generally, such as the health utility index.[
The PubMed MEDLINE and Google scholar databases were utilized to conduct a literature review. The Modified Rankin Scale (mRS), The Glasgow Outcome Scale (GOS), and The Karnofsky Performance Scale (KPS) data were retrieved and analyzed.
The original goal of establishing a uniform shared language for the precise categorization, quantification, and evaluation of patients’ results has been undermined. Furthermore, the KPS may provide a basis for establishing a unified approach to outcome measures. It may provide a straightforward, internationally standardized approach to outcome measurements in neurosurgery and elsewhere after clinical testing and customization. In addition, based on our analysis, the KPS may provide a basis for establishing a unified global measure.
Vascular neurosurgery – The mRS
Vascular neurosurgery is mainly concerned with managing aneurysmal disease, vascular malformation, and ischemic and hemorrhagic stroke. One of the commonly used tools in vascular neurosurgery and especially in stroke trials is the mRS.[
Primarily, the mRS has been used in adult cerebrovascular disease, particularly in stroke trials.[
Traumatic neurosurgery – The GOS
Traumatic neurosurgery is mainly concerned with the management of all blunt and penetrating brain injuries. Outcome measures for traumatic brain injury (TBI) exceed any other neurosurgical sub-specialty, with close to 100 measures.[
The GOS was first described in 1975 by Drs Bryan Jennet and Michael Bond.[
Moreover, the GOS and GOSE measures have continued to be used in line with their original aim, which is traumatic head injuries.[
Oncologic neurosurgery – The KPS
Oncologic neurosurgery is mainly concerned with the management of all intracranial neoplastic tumors. Outcome measures of this subspecialty are crucial to assess the patient’s response to different treatments. The KPS is one of the oldest, most widely used, and evaluated outcome measures in oncology. Its uses have ranged from treatment planning to prognostic assessments.[
In 1948, the KPS was introduced by Dr. David Karnofsky to evaluate patients undergoing treatment with nitrogen mustard for bronchogenic carcinoma.[
Primarily, the KPS has been widely used to measure cancer patients’ functioning and the extent of disability. This has ranged widely from the brain to prostate cancer.[
A comparative analysis
All three discussed scales are the most popular outcome measures in the major subspecialties of adult neurosurgery (vascular, traumatic, and oncologic) as examples of common targets between them which are the consciousness status and the neurological deficit measures. The oldest one of these three measures is the KPS (1948) followed by mRS (1957) and finally GOSE (1998). In terms of simplicity, the mRS is relatively the least comprehensive of the three tools, scored on a 7-point scale of which two are ‘no symptoms and ‘death’, whereas the KPS, scored on a 10-point scale with specific criteria, is the most comprehensive one. The GOSE, in terms of simplicity versus comprehensiveness, is most closely similar to the mRS. However, the GOSE is the only scale of the three to differentiate between upper and lower limb disability, which may offer an advantage for an accurate assessment of these regions. For both the KPS and GOSE scales, a higher number indicates a better state, whereas for the mRS a higher number indicates worse status.
The KPS offers the most patient-friendly utility in terms of communication with patients and relatives. Moreover, this is due to its structure as a “percentage of ability” where 100% refers to a disease-free individual, 50% is a disabled person requiring hospitalization or the equivalent, unable to care for themselves, and 0% is a dead individual. As such, the KPS can be argued to be the most intuitive of the three. In addition, while the mRS focuses mainly on the ability to care for oneself and ambulate, the KPS and GOSE differentiate between various forms of “self-care” that fall under activities of daily living, such as being able to resume work and previous activities [
Regarding the reliability and validity of each measure, it is difficult to compare and draw conclusions due to the wide variation in study designs and findings in the literature over the years. Therefore, to accurately compare each measure, validity and reliability study needs to be conducted for all three measures under the same conditions.
It is worth noting that all three scales serve the same purpose at the core: describing and classifying a patient’s functional and physical abilities. However, none of the scales measure psychosocial aspects of disease and recovery.
Potential, advantages, and disadvantages of a unified outcome measure
With over 100 different outcome measures in the literature, the original objective of establishing a standardized, common language for accurately categorizing, quantifying, and evaluating patients’ outcomes which have been eroded. For this reason, a call for a unified approach to outcome measures is warranted.
By reviewing the history of origin for the three commonest scales, it becomes clear that the main factor behind the use of these scales in a specific field can be traced back to their initial historical use. Naturally, when a researcher publishes within their field, their work is disseminated and most likely to influence other researchers and practitioners within the same field. As such, innovations tend to lag in transcending between specialties and sub-specialties, leading to their restricted adoption within the niche community, it was first intended.
As can be drawn from an analysis of the three scales, they are more similar than dissimilar and can be applied equally to each sub-specialty. The KPS, in particular, may provide a common ground for initiating a unified approach to outcome measures. In addition, this unification considers its comprehensiveness, tested reliability and validity, intuitiveness, broad uses, and clear, descriptive criteria. In addition, the KPS is already used diversely in various fields that deal with cancer and may have the highest tendency of success in new applications. With clinical testing and modification, it may offer a simple, internationally standardized approach to outcome measures in neurosurgery and elsewhere.
The unified global approach to outcome measures may have advantages in clinical practice and research; it facilitates communication, patient handover, and consultations across different sub-specialties and centers and allows for accurate comparisons between trials and patient populations. These considerations may prove highly rewarding concerning patient outcomes, neurosurgeons’ practice, and researchers’ efforts. On the other hand, a unified approach to outcome measures may not be appropriate in all settings, as subtle differences may be required according to the particular needs of each subspecialty. Moreover, the future direction of measuring the quality of life in neurosurgery is getting more specialized and focused, and there is a need for disease-specific outcome measures to ensure an accurate assessment of the patients.[
Quality of life as end-point
In modern-day practice, quality of life has become a critical target, particularly in the field of neurosurgery. Schwartz et al. pointed out in their study (they utilized mRS scale in the study) on the neurological outcome and quality of life in patients with world federation of neurosurgical societies Grades 4 and 5 aneurysmal subarachnoid hemorrhages in their center that younger ages (<53 years) and radiological absence of cerebral ischemia were significantly associated with favorable outcome in the quality of life.[
The article represented a narrative review of the literature regarding the outcome measures in neurosurgery; however, a systematic review of the literature on this topic may redeem better cultivation of the subject. Our study focuses on the targets of consciousness status and neurological deficits in the outcome measures, mainly with examples applied in vascular, trauma, and oncology. Moreover, a suggested systematic review in the future that encompasses all the target measures in outcome in all possible sub-specialties within neurosurgery would add more clarification to the debates about the outcome measures.
Outcome measures in neurosurgery, like “The Modified Rankin Scale, The Glasgow Outcome Scale, and The Karnofsky Performance Scale” are commonly utilized assessment tools for patients’ outcomes in various neurosurgical diseases. A unified global measure may provide a solution with ease of use and application; however, there are limitations.
Patient’s consent not required as there are no patients in this study.
There are no conflicts of interest.
The views and opinions expressed in this article are those of the authors and do not necessarily reflect the official policy or position of the Journal or its management. The information contained in this article should not be considered to be medical advice; patients should consult their own physicians for advice as to their specific medical needs.
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