The Research Of Quantitative Sensory Testing Between Pre-surgery And Post-surgery In Patients With Lumber Disc Herniation

Background:As a tool for quantitative assessment of sensory function,quantitative sensory testing（QST）is a non-invasive and simple method for evaluating the function of large and small nerve fibers.It is widely applied in peripheral nerve diseases.Besides,it is gradually being applied in the research on the spine.Previous studies have investigated sensory recovery in patients with lumbar disc herniation through very subjective methods.At present,there have been fewer reports on changes of sensory function in patients suffering from a preoperative and postoperative sensory deficit through QST.By means of QST analysis on the affected and unaffected areas of the body,people can more thoroughly assess lumbar disc herniation symptoms,and determine the extent of local hypoesthesia and hyperalgesia.Purpose:The paper aims to assess the changes in preoperative and postoperative QST parameters in patients with lumbar disc herniation and their relationship with clinically relevant indicators（such as VAS scores）.Besides,the paper aims to assess the recovery of preoperative sensory dysfunction after lumbar sequestrectomy and to quantify the strength of relationship between a sensory deficit and the patient’s pain.Methods:In this study,a total of 30（18 male and 12 female）patients who were admitted to a Hospital from May 2020 to January 2021,and diagnosed as L4/5 or L5/S1 unilateral lumbar intervertebral disc protrusion caused by posterolateral lumbar disc after detailed interrogation,physical examination,imaging examination were selected.The quantitative temperature detection threshold of the skin of the symptomatic side of the leg and the contralateral mirror site was measured in the nerve root innervation area of the patients’ legs.To be specific,thigh: L5 outer thigh;S1 posterior thigh;calf: L5 lateral calf;S1Posterior leg;Feet: L5 medial feet;S1 Lateral foot.Cold detection threshold（CDT）,warm detection threshold（WDT）,cold pain threshold（CPT）,heat pain threshold（HPT）and VAS scores were measured on symptom side and control side respectively before surgery and one week after surgery.Statistical analysis was conducted on the measured data.Moreover,the symptomatic side and the control side were compared through independent sample t test,and the ipsilateral preoperative and postoperative data were compared through paired sample t test.The correlation between QST index（independent variable）and pain assessment results（dependent variable）was analyzed by linear regression,and p< 0.05 was considered statistically significant.Results:A total of 30 patients met the inclusion criteria,including 18 males and 12 females,at the age of 27～64,with an average age of 44.1±11.5years.Postoperative VAS score of the patients（2.5±1）was significantly lower than preoperative one（6.5±2）,and p<0.05.Disc surgery significantly reduced the patients’ leg pains and obviously improved their quality of life.The preoperative thermal perception threshold presented an obvious contralateral differences: CDT 24.86±3.2℃ vs 28.12±1.38℃,CPT 25.70±2.84℃ vs 28.28±1.27℃,（p<0.005）.There were also contralateral differences between the cold detection threshold（CDT）and the cold pain threshold（CPT）at 1 week after surgery: CDT 25.70±2.84℃vs 28.28±1.27℃,CPT 12.85±3.37℃ vs 19.01±1.90℃,（p<0.005）;there was no significant difference between WDT and HPT（p>0.05）.As for the comparison of the preoperative and postoperative QST measurements on symptom side of patients,there were significant differences in CDT,WDT and CPT before and after surgery（p<0.005）,while there were no significant differences in HPT before and after surgery（p> 0.05）.There was no correlation between CDT and VAS（p>0.05）.WDT was correlated with VAS（p< 0.05）.Both CPT and HPT were highly correlated with VAS（p< 0.005）.Conclusion:The current research result show that the patients with lumbar disc herniation feel subjective and quantifiable improvement in postoperative sensory dysfunction,and that their postoperative pains is greatly relieved.Therefore,QST can objectively measure the pain of patients with lumbar disc herniation.