Objective: Surgery for lumbar disk herniation (LDH) presents an option for patients when conservative measures fail. The objective of this clinical study is to investigate a novel, objective outcome measure in patients undergoing lumbar microdiscectomy.
Methods: Twenty-four patients were evaluated pre- and postoperatively using the Oswestry Disability Index (ODI), and a novel objective scoring tool, the Gait Posture index (GPi). The score is calculated from 4 key physical health metrics: daily step count, walking speed, step length, and walking posture. The GPi ranges from 0 (nonambulant) to 100 (excellent walking performance). Wearable accelerometers and observational recordings were used to evaluate the components of the GPi. The GPi was calculated and compared with the ODI, pre- and postintervention. The study was designed as a proof of concept and confirmation of validity for use of the GPi in LDH.
Results: At follow-up (average 66 ± 36 days), 23 of 24 patients had an improvement in their GPi after surgery. The average GPi of the cohort improved from 59.33 ± 16.06 to 85.75 ± 9.22 with P < 0.001, with significant changes in all 4 components. The average preoperative ODI was 54.54 ± 20.70, improving to 16.33 ± 14.095 with P < 0.001. The Pearson correlation coefficient was r = 0.56, indicating a correlation between change in ODI and change in GPi.
Conclusions: The GPi score is a new, objective descriptor of mobility in spinal surgery which can be used to augment traditional subjective outcome scoring surveys such as the ODI. Significant changes are seen in the GPi and its constituent metrics in patients undergoing surgery for LDH.
Keywords: GPi; Gait Posture index; Lumbar disk herniation; Microdiscectomy; ODI; Spine.
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