Neural activation for actual and imagined movement following unilateral hand transplantation: a case study

ABSTRACT

Transplantation of a donor hand has been successful as a surgical treatment following amputation, but little is known regarding the brain mechanisms contributing to the recovery of motor function. We report functional magnetic resonance imaging (fMRI) findings for neural activation related to actual and imagined movement, for a 54-year-old male patient, who had received a donor hand transplant 50 years following amputation. Two assessments, conducted 3 months and 6 months post-operatively, demonstrate engagement of motor-control related brain regions for the transplanted hand, during both actual and imagined movement of the fingers. The intact hand exhibited a more intense and focused pattern of activation for actual movement relative to imagined movement, whereas activation for the transplanted hand was more widely distributed and did not clearly differentiate actual and imagined movement. However, the spatial overlap of actual-movement and imagined-movement voxels, for the transplanted hand, did increase over time to a level comparable to that of the intact hand. At these relatively early post-operative assessments, brain regions outside of the canonical motor-control networks appear to be supporting movement of the transplanted hand.     

Horizontal impaction of primary mandibular bilateral central incisors identified in 2-year-8-month-old girl

A girl aged 2 years and 8 months came to our clinic for consultation with regard to unerupted primary mandibular bilateral central incisors. An intraoral examination revealed that the teeth had not emerged into the oral cavity and showed a tooth crown morphology similar to that of the primary mandibular incisors, which appeared in the lingual submucosal area outside of the mandibular dental arch. Periapical radiographs demonstrated that the tooth crowns of both affected teeth were severely displaced to the lingual side. Computed tomography examinations were performed to clarify the three-dimensional positions of the affected teeth and their permanent successors, which revealed that the affected teeth were located in their estimated positions and had a standard root morphology. In addition, the permanent successors, which had not initiated root formation, were located close to the affected teeth. We decided to postpone extraction of the affected teeth and perform periodical examinations until the roots of the permanent successors are sufficiently formed. At the age of 2 years and 10 months, the edge of the tooth crown of the primary mandibular left central incisor was found emerged into the oral cavity. According to her parents, the patient did not complain of the emerging edge and no abnormal conditions were observed around the tooth.     

Cost-effectiveness of bone densitometry among Caucasian women and men without a prior fracture according to age and body weight

Summary

We used a microsimulation model to estimate the threshold body weights at which screening bone densitometry is cost-effective. Among women aged 55–65 years and men aged 55–75 years without a prior fracture, body weight can be used to identify those for whom bone densitometry is cost-effective.

Introduction

Bone densitometry may be more cost-effective for those with lower body weight since the prevalence of osteoporosis is higher for those with low body weight. Our purpose was to estimate weight thresholds below which bone densitometry is cost-effective for women and men without a prior clinical fracture at ages 55, 60, 65, 75, and 80 years.

Methods

We used a microsimulation model to estimate the costs and health benefits of bone densitometry and 5 years of fracture prevention therapy for those without prior fracture but with femoral neck osteoporosis (T-score?≤??2.5) and a 10-year hip fracture risk of ≥3%. Threshold pre-test probabilities of low BMD warranting drug therapy at which bone densitometry is cost-effective were calculated. Corresponding body weight thresholds were estimated using data from the Study of Osteoporotic Fractures (SOF), the Osteoporotic Fractures in Men (MrOS) study, and the National Health and Nutrition Examination Survey (NHANES) for 2005–2006.

Results

Assuming a willingness to pay of $75,000 per quality adjusted life year (QALY) and drug cost of $500/year, body weight thresholds below which bone densitometry is cost-effective for those without a prior fracture were 74, 90, and 100 kg, respectively, for women aged 55, 65, and 80 years; and were 67, 101, and 108 kg, respectively, for men aged 55, 75, and 80 years.

Conclusions

For women aged 55–65 years and men aged 55–75 years without a prior fracture, body weight can be used to select those for whom bone densitometry is cost-effective.     

Pericardial Patch Ring Roux-en-Y Gastric Bypass: A Preliminary Report

Background

Laparoscopic Roux-en-Y gastric bypass (RYGB) is an effective treatment for morbid obesity. Failure of weight loss has been reported in 10 to 30 % of RYGB patients. Silastic ring RYGB was introduced to minimize failure rate, however, with higher complication rate. The aim of our study is to evaluate the safety of utilizing pericardial patch as a ring on RYGB patients.

Methods

Between March 2010 and June 2011, a total of 189 patients underwent pericardial patch ring RYGB at the Bariatric and Laparoscopy Center. A retrospective review of a prospectively collected database was performed for all pericardial patch ring RYGB patients, noting the outcomes and complications of the procedure.

Results

Pericardial patch ring RYGB patients demonstrated a mean percentage of excess weight loss of 57.4 % at a mean follow-up of 11 months. Out of 164 patients with follow-up, five (3.0 %) patients required endoscopic balloon dilation due to dysphagia, abdominal pain, and/or gastric outlet obstruction. All patients did well after the procedure. Three (1.8 %) patients underwent diagnostic laparoscopy for abdominal pain. Of these patients, one (0.6 %) had dilated and enlarged blind limb, and two (1.2 %) patients had partial small bowel obstruction. No patient was readmitted or reoperated due to pericardial patch ring.

Conclusions

Longer follow-up is needed to prove the true efficacy of this procedure in reducing weight gain. Pericardial patch ring RYGB seems to be a safe alternative for banded RYGB of other materials.     

Bariatric Surgery Patients Exhibit Improved Memory Function 12 Months Postoperatively

Background

Previous work from our group demonstrated improved memory function in bariatric surgery patients at 12 weeks postoperatively relative to controls. However, no study has examined longer-term changes in cognitive functioning following bariatric surgery.

Methods

A total of 137 individuals (95 bariatric surgery patients and 42 obese controls) were followed prospectively to determine whether postsurgery cognitive improvements persist. Potential mechanisms of change were also examined. Bariatric surgery participants completed self-report measurements and a computerized cognitive test battery prior to surgery and at 12-week and 12-month follow-up; obese controls completed measures at equivalent time points.

Results

Bariatric surgery patients exhibited cognitive deficits relative to well-established standardized normative data prior to surgery, and obese controls demonstrated similar deficits. Analyses of longitudinal change indicated an interactive effect on memory indices, with bariatric surgery patients demonstrating better performance postoperatively than obese controls.

Conclusions

While memory performance was improved 12 months postbariatric surgery, the mechanisms underlying these improvements were unclear and did not appear attributable to obvious postsurgical changes, such as reductions in body mass index or comorbid medical conditions. Future studies employing neuroimaging, metabolic biomarkers, and more precise physiological measurements are needed to determine the mechanisms underlying memory improvements following bariatric surgery.     

Improved Fracture Risk Assessment Based on Nonlinear Micro‐Finite Element Simulations From HRpQCT Images at the Distal Radius

More accurate techniques to estimate fracture risk could help reduce the burden of fractures in postmenopausal women. Although micro‐finite element (µFE) simulations allow a direct assessment of bone mechanical performance, in this first clinical study we investigated whether the additional information obtained using geometrically and materially nonlinear µFE simulations allows a better discrimination between fracture cases and controls. We used patient data and high‐resolution peripheral quantitative computed tomography (HRpQCT) measurements from our previous clinical study on fracture risk, which compared 100 postmenopausal women with a distal forearm fracture to 105 controls. Analyzing these data with the nonlinear µFE simulations, the odds ratio (OR) for the factor‐of‐risk (yield load divided by the expected fall load) was marginally higher (1.99; 95% confidence interval [CI], 1.41–2.77) than for the factor‐of‐risk computed from linear µFE (1.89; 95% CI, 1.37–2.69). The yield load and the energy absorbed up to the yield point as computed from nonlinear µFE were highly correlated with the initial stiffness (R² = 0.97 and 0.94, respectively) and could therefore be derived from linear simulations with little loss in precision. However, yield deformation was not related to any other measurement performed and was itself a good predictor of fracture risk (OR, 1.89; 95% CI, 1.39–2.63). Moreover, a combined risk score integrating information on relative bone strength (yield load‐based factor‐of‐risk), bone ductility (yield deformation), and the structural integrity of the bone under critical loads (cortical plastic volume) improved the separation of cases and controls by one‐third (OR, 2.66; 95% CI, 1.84–4.02). We therefore conclude that nonlinear µFE simulations provide important additional information on the risk of distal forearm fractures not accessible from linear µFE nor from other techniques assessing bone microstructure, density, or mass. © 2013 American Society for Bone and Mineral Research.     

Adult patients' adjustability to orthodontic appliances. Part I: a comparison between Labial, Lingual, and Invisalign™

This prospective study examined the adult patient's perception of recovery after insertion of three types of orthodontic appliances: Buccal, Lingual and Invisalign. The sample consisted of sixty-eight adult patients (45 females and 23 males) who comprised three groups: 28 Buccal, 19 Lingual, and 21 Invisalign patients. After appliance insertion, patients completed a Health-Related Quality of Life questionnaire daily for the first week and again on day 14, in order to assess patients' perception of pain and analgesic consumption. In addition, four areas of dysfunction were assessed: oral dysfunction, eating disturbances, general activity parameters, and oral symptoms. Lingual appliance was associated with more severe pain and analgesic consumption, the greatest oral and general dysfunction, and the most difficult and longest recovery. The Invisalign patients complained of relatively high levels of pain in the first days after insertion; however this group was characterized by the lowest level of oral symptoms and by a similar level of general activity disturbances and oral dysfunction compared to the Buccal appliance. Many Lingual and some Buccal patients did not reach a full recovery from their eating difficulties by the end of the study period. The present study provides information to adult patients and clinicians assisting them in choosing the most appropriate treatment modality in relation to Health-Related Quality of Life parameters.