Mice lacking perforin have improved regeneration of the injured femoral nerve

The role that the immune system plays after injury of the peripheral nervous system is still not completely understood.Perforin,a natural killer cell-and T-lymphocyte-derived enzyme that mediates cytotoxicity,plays important roles in autoimmune diseases,infections and central nervous system trauma,such as spinal cord injury.To dissect the roles of this single component of the immune response to injury,we tested regeneration after femoral nerve injury in perforin-deficient(Pfp^(-/-))and wild-type control mice.Single frame motion analysis showed better motor recovery in Pfp^(-/-)mice compared with control mice at 4 and 8 weeks after injury.Retrograde tracing of the motoneuron axons regrown into the motor nerve branch demonstrated more correctly projecting motoneurons in the spinal cord of Pfp^(-/-)mice compared with wild-types.Myelination of regrown axons measured by g-ratio was more extensive in Pfp^(-/-)than in wild-type mice in the motor branch of the femoral nerve.Pfp^(-/-)mice displayed more cholinergic synaptic terminals around cell bodies of spinal motoneurons after injury than the injured wild-types.We histologically analyzed lymphocyte infiltration 10 days after surgery and found that in Pfp^(-/-)mice the number of lymphocytes in the regenerating nerves was lower than in wild-types,suggesting a closed blood-nerve barrier in Pfp^(-/-)mice.We conclude that perforin restricts motor recovery after femoral nerve injury owing to decreased survival of motoneurons and reduced myelination.

Effect of Ketoprofenphonophoresis and Femoral Nerve Block in Knee Osteoarthritis

Objective:To evaluate the effect of ketoprofenphonophoresis and femoral nerve block in knee osteoarthritis.Methods:One hundred and fourteen patients with knee osteoarthritis were randomly divided into two groups.The control group consisted of 57 patients who were treated with only ketoprofenphonophoresis.The experimental group consisted of patients were treated with ketoprofenphonophoresis and femoral nerve block.The patients were followed for more than one month.The treatment effect assessed by observing their WOMAC index before and after therapy.Results:All the patients finished the follow-up.Their WOMAC indexes were reduced after therapy and one month after treatment,especially in the experimental group(P<0.05).The effective efficiency of ketoprofenphonophoresis and femoral nerve block were higher than that in the control group after treatment and after one month of follow-up(P<0.05).Conclusion:Compared with only ketoprofenphonophoresis,the combined treatment of ketoprofenphonophoresis and femoral nerve block was more appropriate in knee osteoarthritis.

Ultrasonographic identification of lateral femoral cutaneous nerve anatomical variation in persistent meralgia paresthetica:A case report

BACKGROUND Meralgia paresthetica(MP)is an entrapment mononeuropathy of the lateral femoral cutaneous nerve(LFCN).Although structural abnormalities in nerve tissues can be confirmed using ultrasonography,this is not routinely performed.CASE SUMMARY Herein,we present the case of a 52-year-old woman who developed MP after laparoscopic gynecological surgery.The patient was referred to our clinic from an obstetrics and gynecology clinic with symptoms of numbness and a tingling sensation in the left anterolateral thigh,which developed after surgery performed 5 mo earlier.Tests were performed to assess the disease status and determine the underlying causes.Ultrasonographic examination revealed an anatomical variation,where the left LFCN was entrapped within the inguinal ligament.This case suggests that performing ultrasonographic examination before and after surgery in the lithotomy position could help prevent MP.CONCLUSION This case demonstrates the value of ultrasonography in detecting anatomical variation and diagnosing persistent MP.Ultrasonography should be considered an adjunct to electromyography for optimal MP management.Further,this case would help other clinicians determine patient prognosis and decide on targeted treatment strategies.

Repair and regeneration of peripheral nerve injuries that ablate branch points

The peripheral nervous system has an extensive branching organization, and peripheral nerve injuries that ablate branch points present a complex challenge for clinical repair. Ablations of linear segments of the PNS have been extensively studied and routinely treated with autografts, acellular nerve allografts, conduits, wraps, and nerve transfers. In contrast, segmental-loss peripheral nerve injuries, in which one or more branch points are ablated so that there are three or more nerve endings, present additional complications that have not been rigorously studied or documented. This review discusses:(1) the branched anatomy of the peripheral nervous system,(2) case reports describing how peripheral nerve injuries with branched ablations have been surgically managed,(3) factors known to influence regeneration through branched nerve structures,(4) techniques and models of branched peripheral nerve injuries in animal models, and(5) conclusions regarding outcome measures and studies needed to improve understanding of regeneration through ablated branched structures of the peripheral nervous system.

The anatomical,electrophysiological and histological observations of muscle contraction units in rabbits:a new perspective on nerve injury and regeneration

In the conventional view a muscle is composed of intermediate structures before its further division into microscopic muscle fibers.Our experiments in mice have confirmed this intermediate structure is composed of the lamella cluster formed by motor endplates,the innervating nerve branches and the corresponding muscle fibers,which can be viewed as an independent structural and functional unit.In this study,we verified the presence of these muscle construction units in rabbits.The results showed that the muscular branch of the femoral nerve sent out 4–6 nerve branches into the quadriceps and the tibial nerve sent out 4–7 nerve branches into the gastrocnemius.When each nerve branch of the femoral nerve was stimulated from the most lateral to the medial,the contraction of the lateral muscle,intermediate muscle and medial muscle of the quadriceps could be induced by electrically stimulating at least one nerve branch.When stimulating each nerve branch of the tibial nerve from the lateral to the medial,the muscle contraction of the lateral muscle 1,lateral muscle 2,lateral muscle 3 and medial muscle of the gastrocnemius could be induced by electrically stimulating at least one nerve branch.Electrical stimulation of each nerve branch resulted in different electromyographical waves recorded in different muscle subgroups.Hematoxylin-eosin staining showed most of the nerve branches around the neuromuscular junctions consisted of one individual neural tract,a few consisted of two or more neural tracts.The muscles of the lower limb in the rabbit can be subdivided into different muscle subgroups,each innervated by different nerve branches,thereby allowing much more complex muscle activities than traditionally stated.Together,the nerve branches and the innervated muscle subgroups can be viewed as an independent structural and functional unit.This study was approved by the Animal Ethics Committee of Peking University People’s Hospital(approval No.2019 PHE027)on October 20,2019.

Comparison of commonly used retrograde tracers in rat spinal motor neurons

The purpose of this study was to investigate the effect of four fluorescent dyes, True Blue（TB）, Fluoro-Gold（FG）, Fluoro-Ruby（FR）, and 1,1′-dioctadecyl-3,3,3′,3′-tetramethylindocarbocyanine perchlorate（Di I）, in retrograde tracing of rat spinal motor neurons. We transected the muscle branch of the rat femoral nerve and applied each tracer to the proximal stump in single labeling experiments, or combinations of tracers（FG-Di I and TB-Di I） in double labeling experiments. In the single labeling experiments, significantly fewer labeled motor neurons were observed after FR labeling than after TB, FG, or Di I, 3 days after tracer application. By 1 week, there were no significant differences in the number of labeled neurons between the four groups. In the double-labeling experiment, the number of double-labeled neurons in the FG-Di I group was not significantly different from that in the TB-Di I group 1 week after tracer application. Our findings indicate that TB, FG, and Di I have similar labeling efficacies in the retrograde labeling of spinal motor neurons in the rat femoral nerve when used alone. Furthermore, combinations of Di I and TB or FG are similarly effective. Therefore, of the dyes studied, TB, FG and Di I, and combinations of Di I with TB or FG, are the most suitable for retrograde labeling studies of motor neurons in the rat femoral nerve.

Implementation science for the adductor canal block:A new and adaptable methodology process

BACKGROUND Following the successful Perioperative Surgical Home(PSH)practice for total knee arthroplasty(TKA)at our institution,the need for continuous improvement was realized,including the deimplementation of antiquated PSH elements and introduction of new practices.AIM To investigate the transition from femoral nerve blocks(FNB)to adductor canal nerve blocks(ACB)during TKA.METHODS Our 13-month study from June 2016 to 2017 was divided into four periods:a three-month baseline(103 patients),a one-month pilot(47 patients),a three-month implementation and hardwiring period(100 patients),and a six-month evaluation period(185 patients).In total,435 subjects were reviewed.Data within 30 postoperative days were extracted from electronic medical records,such as physical therapy results and administration of oral morphine equivalents(OME).RESULTS Our institution reduced FNB application(64% to 3%)and increased ACB utilization(36% to 97%)at 10 mo.Patients in the ACB group were found to have increased ambulation on the day of surgery(4.1 vs 2.0 m)and lower incidence of falls(0 vs 1%)and buckling(5% vs 27%)compared with FNB patients(P<0.05).While ACB patients(13.9)reported lower OME than FNB patients(15.9),the difference(P=0.087)did not fall below our designated statistical threshold of P value<0.05.CONCLUSION By demonstrating closure of the“knowledge to action gap”within 6 mo,our institution’s findings demonstrate evidence in the value of implementation science.Physician education,technical support,and performance monitoring were deemed key facilitators of our program’s success.Expanded patient populations and additional orthopedic procedures are recommended for future study.

Mobile Bearing Plate Dislocation in Total Knee Arthroplasty Due to Muscle Spasm:A Case Report

An unusual case of early dislocation of a mobile bearing posterior stabilized total knee arthroplasty in a 48-year-old Caucasian woman is described. Dislocation occurred one day postoperatively, attributed to a gap mismatch. Revision surgery reduced posterior dislocation, increased bearing plate thickness and rebalanced ligaments. A second dislocation occurred after revision surgery. The patient’s history was retaken and a hamstring spasm disease identified. A new revision utilized a more constrained design, without perioperative local nerve block. Two years following surgery, no further dislocation had occurred. A numerical musculoskeletal model of the case and implant configuration identified no trend to mobile bearing dislocation when regular muscle forces were applied. Muscle spasm is a risk factor for mobile bearing total knee arthroplasty dislocation, especially with femoral nerve block.

Ultrasound-guided continuous adductor canal block for analgesia after total knee replacement

Background There are several methods for postoperative analgesia for knee surgery.The commonly utilized method is multimodal analgesia based on continuous femoral nerve block.The aim of this study was to investigate the application of continuous adductor canal block for analgesia after total knee replacement and compare this method with continuous femoral nerve block.Methods Sixty patients scheduled for total knee replacement from June 2013 to March 2014 were randomly divided into a femoral group and an adductor group.Catheters were placed under the guidance of nerve stimulation in the femoral group and under the guidance of ultrasound in the adductor group.Operations were performed under combined spinal and epidural anesthesia.After the operations,0.2％ ropivacaine was given at a speed of 5 ml/h through catheters in all patients.Visual analogue scale （VAS） pain scores at rest and while moving were noted at 4,24,and 48 hours after the operation,and quadriceps strength was also assessed at these time-points.Secondary parameters such as doses of complementary analgesics and side effects were also recorded.Results There were no significant differences between the groups in VAS pain scores at rest or while moving,at 4,24,or 48 hours after the operation （P ＞0.05）.At these time-points,mean quadriceps strengths in the adductor group were 3.0 （2.75-3.0）,3.0 （3.0-4.0）,and 4.0 （3.0-4.0）,respectively,all of which were significantly stronger than the corresponding means in the femoral group,which were 2.0 （2.0-3.0）,2.0 （2.0-3.0）,and 3.0 （2.0-4.0）,respectively （P ＜0.05）.There were no significant differences between the groups in doses of complementary analgesics or side effects （P ＞0.05）.X-ray images of some patients showed that local anesthetic administered into the adductor canal could diffuse upward and reach the femoral triangle.Conclusions Continuous adductor canal block with 0.2％ ropivacaine could be used effectively for analgesia after total knee replacement.Compared with continuous femoral nerve block,this analgesic method has similar analgesic effects and is associated with less weakness of quadriceps muscle.