SPINE Volume 31, Number 6, pp 639 – 643 ©2006, Lippincott Williams & Wilkins, Inc. Quality of Life Assessment Using the Short Form-12 (SF-12) Questionnaire in Patients With Cervical Spondylotic Myelopathy Comparison With SF-36 Anoushka Singh, PhD,* Kanna Gnanalingham, FRCS,† Adrian Casey, FRCS,* and Alan Crockard, FRCS* Study Design. Clinical outcome study comparing the Short Form-36 (SF-36) and Short Form-12 (SF-12) assess- ment scales in patients with cervical spondylotic myelop- athy (CSM). Objectives. To compare the validity, reliability, and sensitivity to change of the SF-12 and SF-36 scales in CSM patients undergoing decompressive surgery. Summary of Background Data. The SF-36 is a generic Health Related Quality of Life (HRQoL) questionnaire, consisting of 36 questions that can be reported as a Phys- ical (PCS) and Mental Component Summary (MCS). Re- cently, an abbreviated version of SF-36, the SF-12, which uses only 12 questions drawn from the SF-36, has been described. Methods. In this prospective study, patients with CSM undergoing decompressive surgery, self-completed the SF-36 questionnaire before surgery and at 6 months after surgery. SF-12 item responses were abstracted from the responses given to the SF-36 questionnaire. The validity, reliability, and sensitivity to change of the PCS and MCS components of SF-12 and SF-36 scales were compared. Results. Overall, 105 patients underwent anterior (N = 58) or posterior (N = 47) decompressive surgery. After surgery, there were improvements in the PCS compo- nents of both the SF-36 (40  2 to 54  2) and SF-12 (34  2 to 48  3), as well as in the MCS component of the SF-36 (48  2 to 63  2) and SF-12 (43  2 to 59  2) (P  0.001). The sensitivity to change and absolute sensitivity for both SF-12 and SF-36 were comparable, but the reliability of SF-36 was marginally greater. There were close and linear correlations between the SF-36 and SF-12 scores for both the PCS and MCS components, before and after surgery (R = 0.86 to 0.93; P  0.0001). Conclusions. Both the SF-12 and SF-36 scales are valid and sensitive to changes in physical and mental health sta- tus in CSM patients, undergoing decompressive surgery. Despite its abbreviated nature, the SF-12 appears to be an adequate substitute for SF-36, and its brevity should in- crease its attractiveness to both clinicians and patients. Key words: cervical spondylotic myelopathy, Short Form- 36, Short Form-12, comparison. Spine 2006;31:639 – 643 Cervical spondylotic myelopathy (CSM) is a cause of significant morbidity, and there is ongoing debate as to the value and timing of surgical decompression in this condition. 1 In an attempt to obtain objective data about disease severity and the impact of surgical intervention, a variety of disease-specific and generic assessment scales have been used in CSM patients. 2–11 Generic assessment scales are designed for use in a wide variety of diseases and also tend to be multidi- mensional in assessing Health Related Quality of Life (HRQoL). One of the most popular is the Short Form-36 (SF-36) questionnaire, which is a comprehensive mea- sure of physical and mental HRQoL. 7 It is self- administered and consists of 36 questions that can be grouped in to 1 of 8 health domains and/or reported as a Physical (PCS) and Mental Component Summary (MCS). 7 The reliability and validity of SF-36 have been demonstrated in CSM patients. 8 –11 More recently, an abbreviated version of SF-36, the SF-12, has been de- scribed, which is shorter and therefore quicker to com- plete. 12,13 We compared the validity, reliability, and sen- sitivity to change of the PCS and MCS components of SF-12 and SF-36 in CSM patients undergoing decom- pressive surgery. Methods A total of 105 patients, consecutively referred and accepted for decompressive surgery to the Neurosurgical Unit at the Na- tional Hospital for Neurology and Neurosurgery, were selected for study. The study had local ethical committee approval, and informed consent was obtained from each patient. CSM was diagnosed on the basis of appropriate history, clinical exami- nation, and investigations, notably an MRI scan of the cervical spine. None of the patients had undergone previous neck sur- gery or had other coexisting pathology that might result in functional impairment. The patients were under the care of six consultant neuro- surgeons. The same assessor, an independent nurse practi- tioner, experienced in the use of assessment scales in CSM, evaluated each patient before surgery and at 6 months post- surgery. 11 All patients were given the SF-36 questionnaire to complete, and the nurse practitioner who had no input to the surgical management of the patients was available to answer any queries and to ensure that all parts of the questionnaire were completed. Analysis of the SF-36 and SF-12 Questionnaires. The data from the 36 questions of the SF-36 questionnaire can be From the *Department of Surgical Neurology, National Hospital for Neurology and Neurosurgery, Queen Square, London, UK; and †Department of Neurosurgery, Hope Hospital, Stott Lane, Salford, UK. Acknowledgment date: March 4, 2005. First revision date: March 25, 2005. Acceptance date: March 29, 2005. The manuscript submitted does not contain information about medical device(s)/drug(s). No funds were received in support of this work. No benefits in any form have been or will be received from a commercial party related directly or indirectly to the subject of this manuscript. Address correspondence and reprint requests to Anoushka Singh, PhD, National Hospital for Neurology and Neurosurgery, Box No. 94, Queen Square, London, WC1N 3BG, UK. E-mail: anoushka.singh@uclh.org 639