ABSTRACT
Lumbar disc herniation (LDH) is common and often debilitating. Microdiscectomy of herniated lumbar discs (LDHsurg) is performed on the most severe cases to resolve the resulting sciatica. Here we perform a genome-wide association study on 4,748 LDHsurg cases and 282,590 population controls and discover 37 highly correlated markers associating with LDHsurg at 8q24.21 (between CCDC26 and GSDMC), represented by rs6651255[C] (OR=0.81; P=5.6 × 10-12) with a stronger effect among younger patients than older. As rs6651255[C] also associates with height, we performed a Mendelian randomization analysis using height polygenic risk scores as instruments to estimate the effect of height on LDHsurg risk, and found that the marker's association with LDHsurg is much greater than predicted by its effect on height. In light of presented findings, we speculate that the effect of rs6651255 on LDHsurg is driven by susceptibility to developing severe and persistent sciatica upon LDH.
Subject(s)
Chromosomes, Human, Pair 8/genetics , Genetic Predisposition to Disease , Genetic Variation , Intervertebral Disc Degeneration/genetics , Intervertebral Disc Displacement/genetics , Lumbar Vertebrae/pathology , Sciatica/genetics , Adult , Base Sequence , Body Height/genetics , Demography , Female , Genetic Loci , Humans , Intervertebral Disc Degeneration/surgery , Intervertebral Disc Displacement/surgery , Lumbar Vertebrae/surgery , Male , Middle Aged , Phenotype , Polymorphism, Single Nucleotide/genetics , Risk FactorsABSTRACT
OBJECTIVE: The present follow-up study in 20 women with TMJ pain and reduced mandibular function associated with disc derangement, osteoarthritis, or inflammatory disorders aimed at investigating whether pain reduction was reflected in function. STUDY DESIGN: After 3 years and conventional therapy, 19 of the patients and 15 of the original 20 matched controls completed a questionnaire, including RDC/TMD Jaw Disability Scale and TMJ chewing pain (VAS). Fourteen patients also accepted reexamination comprising TMJ pressure-pain thresholds (PPT), jaw opening, bite force, and jaw kinematics during chewing. RESULTS: VAS was significantly reduced in patients at the follow-up, but PPT was unchanged, and Jaw Disability ratings were significantly higher than in controls. However, the patients' jaw opening, chewing speed, and bite force had increased significantly. CONCLUSION: With reduction of TMJ pain, function improved in patients to a level that approached reference levels, indicating a marked ability of the nervous system in restoring motor activity.
Subject(s)
Mandible/physiopathology , Temporomandibular Joint Disorders/physiopathology , Adult , Arthritis/physiopathology , Arthritis/therapy , Attitude to Health , Bite Force , Case-Control Studies , Facial Pain/physiopathology , Facial Pain/therapy , Female , Follow-Up Studies , Humans , Joint Dislocations/physiopathology , Joint Dislocations/therapy , Mastication/physiology , Middle Aged , Movement , Osteoarthritis/physiopathology , Osteoarthritis/therapy , Pain Threshold/physiology , Physical Examination , Range of Motion, Articular/physiology , Temporomandibular Joint Disc/physiopathology , Temporomandibular Joint Disorders/therapyABSTRACT
AIMS: To evaluate the effect of temporomandibular arthralgia on mandibular mobility, chewing, and bite force. METHODS: Twenty female patients (ages 19 to 45 years) with unilateral temporomandibular joint (TMJ) pain during chewing (49 +/- 27 mm on a 100-mm visual analog scale) and provocation, as well as TMJ tenderness, were studied. The TMJ conditions were classified as disc derangement disorders (n = 9), osteoarthritis (n = 7), and inflammatory disorders (n = 4). The patients were compared with matched healthy volunteers without orofacial pain or tenderness. Exclusion criteria were the presence of fewer than 24 teeth or malocclusion. The methods used were (1) algometric assessment of the pressure pain threshold (PPT) over the TMJ; (2) clinical recordings of maximum jaw opening; (3) computerized kinematic assessment of maximum vertical distance, velocity, and cycle duration during chewing of soft gum; and (4) measurement of unilateral molar bite force. RESULTS: The mean (+/- SD) PPT in the patients' painful side (69 +/- 20 kPa; P = .000001) was significantly lower than in the control subjects (107 +/- 22 kPa). Jaw opening was also significantly less (P = .00003) in the patients (42 +/- 9 mm) than in the controls (52 +/- 4 mm). Chewing cycle duration and maximum closing velocity were significantly different (P < or = .03) in the patients (948 +/- 185 milliseconds and 142 +/- 46 mm/s, respectively) versus the controls (765 +/- 102 milliseconds and 173 +/- 43 mm/s, respectively), and bite force was significantly lower (P = .000003) in the patients (238 +/- 99 N) than in the controls (394 +/- 80 N). Both bite force and jaw opening in patients were significantly correlated (P < or = .02) with PPT (r = 0.53 and 0.63, respectively). CONCLUSION: These systematic findings supplement results from acute pain experiments and confirm indications from unspecified patient groups that the clinical presence of long-standing TMJ pain is associated with marked functional impairment. This impairment might be a result of reflex adaptation and long-term hypoactivity of the jaw muscles.
