Introduction: There is growing interest in Health Related Quality of Life (HRQL) questionnaires to quantitate the impact of a variety of diseases and their treatments. The Short Form-36 (SF3) is a comprehensive measure of health status, consisting of 36 questions related to Physical (PCS) and Mental Component Summary (MCS).1 An abbreviated version of SF36, the SF12 has been described.2 We report on the use of SF12 and SF36 to assess the impact of surgery in patients with cervical spondylotic myelopathy (CSM).

Methods: In this prospective study, patients undergoing anterior or posterior decompressive surgery self completed the SF36 questionnaire pre-operatively and at 6 months post-operatively. The data from the SF36 is categorised into 8 scales: physical functioning (PF), physical role (PR), bodily pain (BP), general health (GH), vitality (VT), social functioning (SF), emotional role (ER) and mental health (MH).1 Each scale is scored on a 0 (maximum disability) to 100 (no disability) metric. These 8 scales are reduced to a Physical (PCS) and Mental Component Summary (MCS).1 SF12 utilises only 12 questions of the 8 scales of the SF36.2 We compared the validity, reliability and sensitivity to change in CSM patients.

Results: We studied 105 patients with a median age of 58. Post-operatively, there were improvements in the PCS components of both the SF36 (40 ± 2 to 54 ± 2) and SF12 (34 ± 2 to 48 ± 3) (p< 0.0001; Wilcoxon Signed Ranks test) and MCS component of SF36 (48 ± 2 to 63 ± 2) and SF12 (43 ± 2 to 59 ± 2) (p< 0.001). There were linear relationships between the SF36 and SF12.

Conclusions: Both the SF12 and SF36 scales are valid and sensitive to changes in CSM patients, undergoing decompressive surgery. Despite its abbreviated nature, SF12 appears to be an adequate substitute for SF36 and its brevity should increase its attractiveness to both the clinicians and patients.

Introduction: Preliminary studies suggest that prolonged retraction of the paraspinal muscle during spinal surgery may produce ischaemic damage. We describe the continuous measurement of intramuscular pressures (IMP) during decompressive lumbar laminectomy and the relationship to back pain and disability.

Methods: In this prospective interventional study, 28 patients undergoing surgery for lumbar canal stenosis were recruited. Back pain and function were assessed using the Visual Analogue Score (VAS), Oswestry Disability Index (ODI) and Short Form 36 (SF36) health survey. During surgery, IMP was continuously recorded from the multifidus muscle using a pressure transducer. The intramuscular perfusion pressure (IPP) was derived as the difference between the patient’s mean arterial pressure (MAP) and IMP (IPP = MAP − IMP). The data was analysed using repeated measures ANOVA (SPSS package).

Results: The mean age was 60.4 ± 3 years and the mean duration of symptoms of 31.0 ± 6 months. The predominant symptoms were neurogenic claudication (14) and/or sciatica (13). Patients underwent 1 (N=3), 2 (N=20) or 3 (N=5) level laminectomies. The muscle retractors used were Norfolk and Norwich (N=16) and McCullock (N=12). The mean duration of deep muscle retraction was 68.5 ± 9 mins (range 19–240). On application of deep muscle retraction, there was a rapid and sustained increase in IMP (F=26.8; p< 0.001; repeated measures ANOVA), and overall the calculated mean IPP approached 0 mmHg or less during this period (F=36.8; p< 0.001). On release of deep muscle retraction there was a rapid decrease in IMP to pre-operative levels. The IPP was greater with Norfolk and Norwich than McCullock retractors (F=12.2; p< 0.001). Compared to pre-operative values, there was a decrease in ODI (F=18.6; p< 0.001) and VAS for back pain (F=9.9; p< 0.001) at discharge, 4–6 weeks and 6 months, post-operatively. Compared to pre-operative values, there was a decrease in SF36 scores at 6 months (F=26.7; p< 0.001). Total duration of muscle retraction over 60 mins was associated with higher VAS scores for back pain at 4–6 weeks and 6 months postoperatively (F=3.7; p< 0.01). There was no relationship between IPP and post-operative ODI or VAS for back pain.

Conclusions: This study demonstrates a simple technique for the continuous monitoring of IMP during spinal surgery, from which the IPP can be derived. Comparison of two muscle retractors has shown that the McCullock retractor generates a higher IMP than Norfolk and Norwich retractor. Decompressive lumbar laminectomy improves the VAS for back pain and ODI and SF36 outcome scores in these patients. The results show that duration of muscle retraction, rather than extent of the pressure generated by the retractor, is related to postoperative back pain.