Size of recurrent laryngeal nerve as a new risk factor for postoperative vocal cord paralysis

Recurrent laryngeal nerve paralysis (RLNP) is a frequent and serious complication following esophageal cancer surgery. Therefore, this study aims to evaluate the correlation between recurrent laryngeal nerve (RLN) size and RLNP. This was a retrospective study of esophageal cancer patients who underwent thoracoscopic esophagectomy from January 2012 to December 2014. Eighty-four patients were included in the primary analysis. Diameter of the RLN was measured using the digital video recording of surgical procedures by the ratio between scissor and RLN. For evaluation of vocal cord paralysis or paresis, indirect laryngoscopy was performed. Because RLNP more frequently occurs on the left side than the right, we evaluated the correlation between size of the left RLN and left RLNP. The median size of the left RLN was 1.51 mm. We found that the incidence of postoperative left RLNP (Clavien-Dindo classification ≥1) was significantly higher (71% vs. 24%; P < 0.001) in thin RLNs (≤1.5 mm) than in thick RLNs (>1.5 mm). Thin RLN (P < 0.001), female sex (P = 0.025), and being overweight (P = 0.034) were identified as significant independent risk factors for postoperative RLNP. RLNP more easily occurred when the RLN was thin. It is difficult to confirm occurrence of postoperative RLNP before and at extubation. Therefore, it is helpful to know its risk factors including size of RLN.

Meta-analysis of the impact of postoperative complications on survival after oesophagectomy for cancer

Background

Oesophagectomy has a high risk of postoperative morbidity. The impact of postoperative complications on overall survival of oesophageal cancer remains unclear. This meta‐analysis addressed the impact of complications on long‐term survival following oesophagectomy.

Methods

A search of PubMed and Cochrane Library databases was undertaken for systematic review of papers published between January 1995 and August 2016 that analysed the relation between postoperative complications and long‐term survival. In the meta‐analysis, data were pooled. The main outcome was overall survival (OS). Secondary endpoints included disease‐free (DFS) and cancer‐specific (CSS) survival.

Results

A total of 357 citations was reviewed; 21 studies comprising 11 368 patients were included in the analyses. Overall, postoperative complications were associated with significantly decreased 5‐year OS (hazard ratio (HR) 1·16, 95 per cent c.i. 1·06 to 1·26; P = 0·001) and 5‐year CSS (HR 1·27, 1·09 to 1·47; P = 0·002). Pulmonary complications were associated with decreased 5‐year OS (HR 1·37, 1·16 to 1·62; P < 0·001), CSS (HR 1·60, 1·35 to 1·89; P < 0·001) and 5‐year DFS (HR 1·16, 1·00 to 1·33; P = 0·05). Patients with anastomotic leakage had significantly decreased 5‐year OS (HR 1·20, 1·10 to 1·30; P < 0·001), 5‐year CSS (HR 1·81, 1·11 to 2·95; P = 0·02) and 5‐year DFS (HR 1·13, 1·02 to 1·25; P = 0·01).

Conclusion

Postoperative complications after oesophagectomy, including pulmonary complications and anastomotic leakage, decreased long‐term survival.

Association between UGT2B7 gene polymorphisms and fentanyl sensitivity in patients undergoing painful orthognathic surgery

Background

Fentanyl is often used instead of morphine for the treatment of pain because it has fewer side effects. The metabolism of morphine by glucuronidation is known to be influenced by polymorphisms of the UGT2B7 gene. Some metabolic products of fentanyl are reportedly metabolized by glucuronate conjugation. The genes that are involved in the metabolic pathway of fentanyl may also influence fentanyl sensitivity. We analyzed associations between fentanyl sensitivity and polymorphisms of the UGT2B7 gene to clarify the hereditary determinants of individual differences in fentanyl sensitivity.

Results

This study examined whether single-nucleotide polymorphisms (SNPs) of the UGT2B7 gene affect cold pain sensitivity and the analgesic effects of fentanyl, evaluated by a standardized pain test and fentanyl requirements in healthy Japanese subjects who underwent uniform surgical procedures. The rs7439366 SNP of UGT2B7 is reportedly associated with the metabolism and analgesic effects of morphine. We found that this SNP is also associated with the analgesic effects of fentanyl in the cold pressor-induced pain test. It suggested that the C allele of the rs7439366 SNP may enhance analgesic efficacy. Two SNPs of UGT2B7, rs4587017 and rs1002849, were also found to be novel SNPs that may influence the analgesic effects of fentanyl in the cold pressor-induced pain test.

Conclusions

Fentanyl sensitivity for cold pressor-induced pain was associated with the rs7439366, rs4587017, and rs1002849 SNPs of the UGT2B7 gene. Our findings may provide valuable information for achieving satisfactory pain control and open to new avenues for personalized pain treatment.

Transversal Width of Mandibular Bone and Neurosensory Disturbance after Bilateral Sagittal Splitting Ramus Osteotomy

Objective

This study evaluated the condition of mandibular cancellous and cortical bone on computed tomography (CT) images in order to investigate its relationship with the incidence of neurosensory disturbances (NSD) in the mental nerve region after bilateral sagittal splitting ramus osteotomy (BSSRO).

Methods

BSSRO was performed on 58 lateral mandibles in 29 patients. From preoperative CT images, the width endpoints of the transversal bone were measured in region I immediately inferior to the mandibular foramen, region II in the mandibular angle region, and region III distal to the lower second molar. The incidence of NSD immediately after surgery and the residual NSD rate at 1, 3, and 6 months after surgery were investigated. The correlation between incidence of NSD in the mental nerve region and each transversal bone width endpoint immediately after and at 6 months after surgery was also comparatively evaluated.

Results

The overall incidence of NSD immediately after surgery was 67.2% (39/58 sides) and the overall residual NSD rate at 1, 3, and 6 months after surgery was 53.4% (31/58 sides), 31.0% (18/58 sides), and 17.2% (10/58 sides), respectively. No significant differences were observed for any width endpoints of the transversal bone measured at regions I or III, but the transversal width of the entire mandible was significantly different in region II between patients with and without NSD at 6 months after surgery (p < 0.05).

Conclusion

These findings demonstrate that the transversal width of the entire mandible may be an important factor in predicting NSD incidence.

Enhancing Survival of Human Hepatocytes by Neonatal Thymectomy and Partial Hepatectomy in Micro-miniature Pigs

BACKGROUND

With the goal of in vivo cultivation of human hepatocytes that have not been sufficient in full differentiation in vitro, the advantage of neonatal thymectomy was verified on expansion of xenogeneic human hepatocyte in the micro-miniature pig (MMP).

METHODS

The thymus was excised immediately after the birth of the MMPs via cesarean section. Newborns were fed by artificial feeding under specific pathogen-free conditions. The thymectomized and nonthymectomized littermates were transplanted with human hepatocytes via a portal vein with or without partial hepatectomy at the MMP adult stage.

RESULTS

The growth of thymectomized MMPs and the sham operated littermates was not significantly different; the former weighed 1.98 ± 0.30 kg (average ± standard deviation, n = 4) and the latter weighed 2.28 ± 0.39 kg (n = 4) at 1 month of age, and 17.48 ± 1.92 kg and 16.75 ± 2.68 kg at 12 months of age. Blood thymosin α₁ concentrations in the thymectomy group were significantly lower than in the control group (0.22 ± 0.05 ng/mL vs 0.46 ± 0.16 ng/mL; n = 4, 12 months old, P = .029). After human hepatocyte transplantation, human albumin levels were detectable on day 28 in the peripheral blood of the thymectomy plus hepatectomy group (14.3 ± 4.9 ng/mL [± range, n = 2]) but were not detectable even on day 21 in the control group.

CONCLUSIONS

Neonatal thymectomy was successfully achieved in infantile MMPs born via cesarean section. These pigs were considered to be an ideal in vivo bioreactor for human hepatocytes.

The use of sonoelastography to assess the recovery of stiffness after equine superficial digital flexor tendon injuries: A preliminary prospective longitudinal study of the healing process

BACKGROUND

The objective assessment of the mechanical properties of the superficial digital flexor tendon (SDFT) could provide useful information for the rehabilitation of horses with SDFT injuries. Assessment of strain ratio (the strain of a standard reference divided by that of lesions) is a quantitative method in sonoelastography for evaluating tissue stiffness in vivo. As yet, no longitudinal studies have used strain ratio to evaluate the progression of stiffness in SDFT injuries.

OBJECTIVES

To test the hypothesis that strain ratio can evaluate the recovery of stiffness during the healing of SDFT injuries.

STUDY DESIGN

Prospective and longitudinal study with observer-blinded evaluation.

METHODS

Ultrasonography, including sonoelastography, was performed in seven Thoroughbred horses with naturally occurring SDFT injuries at five time points: within 20 days of the injury, and at 2, 3, 6 and 9 months after the injury. Blinded sonoelastographic images were independently evaluated by two veterinarians to assess interobserver agreement. The recovery of stiffness and echogenicity in lesions were evaluated using the strain ratio and grey-scale ratio (echogenicity of lesions divided by that of the surrounding area), respectively.

RESULTS

Interobserver agreement was assessed as 'almost perfect'. Strain ratios were significantly higher at 9 months after injury than at the other time points (all P<0.05). Strain ratios at 6 months after injury were significantly higher than those at earlier time points (P<0.05). Grey-scale ratios within 20 days of injury were significantly lower than those at the other time points (all P<0.05).

MAIN LIMITATIONS

Validations of SDFT status were evaluated only by recovery of the echogenicity in lesions and not by histopathological examination.

CONCLUSIONS

Although further studies are needed to validate the relationships between injured SDFT status and sonoelastographic findings, this preliminary study shows that strain ratio may provide a means to monitor the recovery of stiffness in lesions during rehabilitation, even when the grey-scale ratio remains unchanged from a few months after SDFT injury. The Summary is available in Chinese - see Supporting Information.

Application of sonoelastography for evaluating the stiffness of equine superficial digital flexor tendon during healing

Sonoelastography can assess the inner stiffness of tissues. Sonoelastographic evaluation of injured equine superficial digital flexor tendons (SDFTs) is considered to be useful for assessing the stiffness of a lesion even during late-stage rehabilitation. The purpose of this study was to investigate and compare the sonoelastographic appearance of injured SDFTs over time from the onset of the injury. Eighteen horses were classified into three groups according to the length of time from injury onset: group A, within two weeks after injury; group B, approximately five months after injury; and group C, approximately nine months after injury. Longitudinal and transverse images of all injured SDFTs were obtained using grey-scale ultrasonography and sonoelastography. Grey-scale and sonoelastographic images were evaluated by two observers using echogenicity-grading and colour-grading systems, respectively. The authors evaluated the interobserver agreement and compared the grades among the three groups. The results indicated almost perfect interobserver agreement. Significant differences were found in the sonoelastography among the three groups, whereas no significant difference was found in the grey-scale ultrasonography between groups B and C. Sonoelastography is a feasible and useful modality to evaluate the equine injured SDFTs in vivo and to distinguish between them among the different phases even during the chronic phase.

Oliguria without serum creatinine increase after living donor liver transplantation is associated with adverse post-operative outcomes

BACKGROUND

Acute kidney injury (AKI) is a common complication after liver transplantation and is associated with significant morbidity and mortality. Although clinical guidelines recommend defining AKI based on serum creatinine increase and oliguria, the validity and utility of the oliguric component of AKI definition remains largely unexplored. This study examined the incidence and the impact on clinical outcomes of oliguria meeting the urine output criterion of AKI in patients undergoing liver transplantation. The authors hypothesised that oliguria was an independent risk factor for adverse post-operative outcomes.

METHODS

This study retrospectively examined 320 patients who underwent living donor liver transplantation at our centre. AKI stages were allocated according to recent guidelines based on serum creatinine or urine output within 7 days of surgery.

RESULTS

The incidence of oliguria meeting the urine output criterion of AKI was 50.3%. Compared with creatinine criterion alone, incorporating oliguria into the diagnostic criteria dramatically increased the measured incidence of AKI from 39.7% to 62.2%. Compared with patients diagnosed without AKI using either criterion, oliguric patients without serum creatinine increase had significantly longer intensive care unit stays (median: 5 vs. 4 days, P = 0.016), longer hospital stays (median: 60 vs. 49 days, P = 0.014) and lower chronic kidney disease-free survival rate on post-operative day 90 (54.2% vs. 73.3%, P = 0.008).

CONCLUSION

Oliguria is common after liver transplantation, and incorporating oliguria into the diagnostic criteria dramatically increases the measured incidence of AKI. Oliguria without serum creatinine increase was significantly associated with adverse post-operative outcomes.

Analytical approach to the temporal changes in NIRS signals to separate hemodynamic change from brain activity

In brain function measurements by near-infrared spectroscopy (NIRS), we focus on the temporal changes in the oxygenated and deoxygenated hemoglobin concentrations and propose an analytical approach to the temporal changes of the hemoglobin concentrations' cross-correlation coefficient in the brain functional signals. The cross-correlation coefficient between the oxygenated and deoxygenated hemoglobin concentrations shows negative values for brain activity and positive values for hemodynamic changes. Experiments with a 16-channel functional NIRS system show that our proposed approach clarifies the interpretation of the measured NIRS signals and it can be used to estimate the influence of hemodynamic change on brain activity.

Structure of the set of feasible neural commands for complex motor tasks

The brain must select its control strategies among an infinite set of possibilities; researchers believe that it must be solving an optimization problem. While this set of feasible solutions is infinite and lies in high dimensions, it is bounded by kinematic, neuromuscular, and anatomical constraints, within which the brain must select optimal solutions. That is, the set of feasible activations is well structured. However, to date there is no method to describe and quantify the structure of these high-dimensional solution spaces. Bounding boxes or dimensionality reduction algorithms do not capture their detailed structure. We present a novel approach based on the well-known Hit-and-Run algorithm in computational geometry to extract the structure of the feasible activations capable of producing 50% of maximal fingertip force in a specific direction. We use a realistic model of a human index finger with 7 muscles, and 4 DOFs. For a given static force vector at the endpoint, the feasible activation space is a 3D convex polytope, embedded in the 7D unit cube. It is known that explicitly computing the volume of this polytope can become too computationally complex in many instances. However, our algorithm was able to sample 1,000,000 uniform at random points from the feasible activation space. The computed distribution of activation across muscles sheds light onto the structure of these solution spaces-rather than simply exploring their maximal and minimal values. Although this paper presents a 7 dimensional case of the index finger, our methods extend to systems with at least 40 muscles. This will allow our motor control community to understand the distributions of feasible muscle activations, providing important contextual information into learning, optimization and adaptation of motor patterns in future research.

Integrated theory to unify status among schizophrenia and manic depressive illness

Tryptophan hydroxylase 1 is primarily expressed in the gastrointestinal tract, and has been associated with both schizophrenia and depression. Although decreased serotonin activity has been reported in both depression and mania, it is important to investigate the interaction between serotonin and other neurotransmitter systems. There are competitive relationships between branched-chain amino acids, and tryptophan and tyrosine that relate to physical activity, and between L-3,4-dihydroxyphenylalanine (L-DOPA) and 5-hydroxytryptophan (5-HTP), both highly dependent on intracellular tetrahydrobiopterin concentrations. Here, I propose a chaos theory for schizophrenia, mania, and depression using the competitive interaction between tryptophan and tyrosine with regard to the blood-brain barrier and coenzyme tetrahydrobiopterin. Mania may be due to the initial conditions of physical hyperactivity and hypofunctional 5-HTP-producing cells inducing increased dopamine. Depression may be due to the initial conditions of physical hypoactivity and hypofunctional 5-HTP-producing cells inducing decreased serotonin. Psychomotor excitation may be due to the initial conditions of physical hyperactivity and hyperfunctional 5-HTP-producing cells inducing increased serotonin and substantially increased dopamine. The hallucinatory-paranoid state may be due to the initial conditions of physical hypoactivity and hyperfunctional 5-HTP-producing cells inducing increased serotonin and dopamine.