Accuracy of dermatomes in the localization of lumbar disc herniations for pre-operative planning: A systematic review

Introduction: Symptomatic lumbar disc herniations have a prevalence of 1-3% in the general population. Clinical examination is utilized to identify the level of nerve root impingement using pain or sensory changes in dermatomal patterns. These findings are often cited as beneficial for pre-operative planning to localize the level of nerve root impingement in conjunction with advanced imaging. Recent studies have challenged the accuracy of previous dermatomal distributions.Objective: To evaluate the rate of correlation for altered sensation and pain in dermatomal distributions with the specific level of nerve root compression.Methods: A systematic review was performed using PRISMA guidelines. A search was performed on PUBMED/ MEDLINE, Cochrane Database and Embase on 08 OCT 2022. Search keywords were "nerve root, disc herniation, physical examination, lumbar". CT, MRI or intra-operative findings for level of nerve root compression were recorded. Dermatomal pain or sensation on physical examination were compared to the level of nerve root compression. Results: A total of three hundred and forty-seven articles were obtained from the literature search. Eighty-one full length articles were obtained and reviewed. Full data was obtained from seven articles. Overall correlation of physical examination findings with nerve root compression ranged from 5 to 93%. Overall correlation was 42%. L4 correlation ranged from 7.7 to 33%. L5 compression correlated 7.1-41%. S1 physical examination matched 2.4-54%.Conclusion: Dermatomal pain and sensory loss are utilized for identifying nerve root compression. The current systematic review identified an overall correlation of 42% with physical examination for sensory loss and the level of lumbar nerve root compression.