Sensory retraining following orthognathic surgery: effect on threshold measures of sensory function.
ABSTRACT The purpose of this analysis was to examine the effect of sensory retraining on sensory function after bilateral sagittal split osteotomy (BSSO). A total of 186 subjects were enrolled in a multi-centre double-blind two parallel group stratified block randomized clinical trial. Subjects were randomized to group immediately after surgery. Threshold measures for contact detection, two-point discrimination and two-point perception were obtained on the chin before and 1, 3 and 6 months and 1 and 2 years after surgery. The ratio of each threshold measure (post-surgery value/pre-surgery value) was calculated to characterize subjects' impairment. A general linear mixed model was fit for the impairment to examine the effect of the sensory retraining before and after adjusting for demographic, surgical and psychological factors. On average, two-point perception was less impaired in subjects who were retrained than in those who were not retrained (P = 0.04). Significant recovery continued up to 6 months after surgery for contact detection and two-point perception and up to 24 months for two-point discrimination. Older subjects experienced more impairment in two-point discrimination than younger subjects (P = 0.009). Subjects who received maxillary surgery in addition to mandibular surgery experienced more impairment on the chin in both two-point discrimination (P = 0.0003) and perception (P = 0.0013) than subjects who received mandibular surgery only. Psychological factors did not explain additional variability in subjects' impairment post-surgery. These finding indicate that a simple non-invasive exercise programme initiated shortly after orthognathic surgery can alter the way patients experience or respond to tactile stimulation long after the exercise regimen has stopped.
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ABSTRACT: The purpose of this study was to review the current literature for the relationship between the preoperative position of the mandibular canal on three-dimensional (3D) radiographic imaging and postoperative neurosensory disturbance (NSD) following a sagittal split ramus osteotomy (SSRO). A literature search was conducted using PubMed, EMBASE, and the Cochrane Database for articles published from 1 January 2000 through 31 December 2013. Studies that included preoperative 3D imaging and assessment of NSD after surgery were reviewed. Study sample characteristics and results were extracted. Of the 69 articles identified, seven met the inclusion and exclusion criteria. There was no standardization for measuring the canal position or for evaluating NSD. General consensus was that the less space between the mandibular canal and the outer border of the buccal cortex the more frequent the occurrence of NSD. Increased bone density also appeared to contribute to a higher incidence of NSD. Utilization of 3D images to locate and measure the position of the mandibular canal is not standardized. Advances in 3D imaging and evaluation tools allow for new methodologies to be developed. Early attempts are informative, but additional studies are needed to verify the relationship between the location of the nerve and NSD following surgery.International Journal of Oral and Maxillofacial Surgery 05/2014; 43(9). DOI:10.1016/j.ijom.2014.03.020 · 1.52 Impact Factor
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ABSTRACT: The aim of the study was to obtain pilot data on the putative effects of intranasal spray Vitamin B12 in lessening the impairment from orthognathic surgery on large and small diameter nerve fiber functions. Thirty-five subjects scheduled for a mandibular osteotomy were enrolled in an open-label two-group parallel stratified-block randomized clinical trial: Intranasal Vitamin B12 Spray (B12), with weekly doses self-administered two weeks before until 6 months after surgery, or no intranasal spray. All subjects received sensory retraining exercises. Large fiber tactile (contact detection) and small fiber thermal (warm, cool, heat discomfort, and cold discomfort) thresholds were obtained before and at 1, 3, and 6 months after surgery. For each, the mean maximum impairment was estimated for group and visit, controlling for age and type of surgery. The demographics and pre-surgery threshold values of the two groups did not differ (P>0.16). At and 6 months after surgery, serum B12 levels were substantially higher in the B12 group (P<0.01). At one month post, average impairment for every threshold measure was less for the B12 group. From 1 to 3 months, the differences between the two groups decreased for the tactile measures but stayed the same (cool and warm perception) or increased (cold and heat discomfort perception) for the thermal measures. At 6 months, the B12 group remained less impaired for the thermal measures. This pilot RCT indicates that the effects of intranasal Vitamin B12 spray, initiated prior to surgery, on sensory function are sufficiently promising to justify progression to a Phase III RCT.04/2012; 1(1):20-29.