Major Nerve Research Articles

Outcomes of Vascular Resection and Reconstruction in Extremity Soft Tissue Sarcoma and Bone Tumors.

PurposeThis study aimed to evaluate and analyze the feasibility and the oncological and functional outcomes of limb salvage surgery in extremity soft tissue sarcomas (ESTS) and bone tumors invading vessels.MethodsMaterials and This single-center retrospective analysis included patients with ESTS encasing or invading major blood vessels that were treated by limb salvage surgery with vascular resection and reconstruction between January 1995 and December 2019. Patients with contiguous involvement of major blood vessels and nerves and patients requiring amputation were excluded from the study.ResultsA total of 24 vessels (14 arteries and 10 veins) in 14 patients were reconstructed. Ten (71.4%) patients underwent both arterial and venous reconstruction, and four (28.6%) underwent only arterial reconstruction. Reconstruction was performed with a reversed saphenous vein (RSV) graft in 12 patients and with a synthetic graft (SG) in the other 12 patients. At a median follow-up of 27 months, RSV grafts were patent in 10 of 12 (83.3%) vessels and SGs were patent in 6 of 12 (50.0%) vessels (log-rank test, P=0.083). Out of 14 arteries and 10 veins, 11 arteries and 5 veins were patent, respectively. No patient developed local recurrence, and 2 (14.3%) patients developed distant metastases. Limb salvage rate was 13/14 (92.9%). The mean Musculoskeletal Tumor Society score was 83.3%. The 5- and 10-year overall survival rates were 80% and 50%, respectively.ConclusionLimb salvage surgery in ESTS with vascular resection and reconstruction is feasible and provides favorable oncological and functional outcomes.

Two cases of plexiform neurofibromatosis at unusual sites

Plexiform neurofibromatosis (PNF) is a potentially devastating type of neurofibromatosis, but is rare to occur. PNFs are benign tumours that originate from nerve sheath cells, visceral or subcutaneous peripheral nerves that can involve multiple fascicles and present as large tumours attached to major nerves. They are associated with NF-1 lesions in majority of cases and present with bulging and deforming masses involving skin folds and connective tissue most commonly at sites of trigeminal nerve distribution, and may also present as isolated lesions. There are high chances of malignant transformation in these lesions and thus should not be left untreated. Due to paucity of options available for treatment, surgical debulking remains the most important management. Being an autosomal dominant disorder, genetic counseling is necessary. We are presenting two cases of PNFs, occurring at unusual sites like sole of foot and forearm. Keywords: Plexiform neurofibroma, Tumour, Nerves.

Assessing the innervation of the dorsal wrist capsule using modified Sihler's staining.

The aim of this study was to assess the innervation of the dorsal articular capsule of the wrist using modified Sihler's staining. Thirty dorsal wrist capsules were collected from 15 donors (both sides) within 12 hours of death. All the capsules were collected in the same manner - using the dorsal incision. The specimens were stained according to the protocol of the modified Sihler's staining technique. The preserved capsules were analysed under 8-16× magnification of an optical microscope for the presence of major nerve trunks, their major and minor branches, and nerve connections. The range of innervation visualised was that the posterior interosseous nerve innervated approximately 60% of the central part; the remaining area was innervated by the dorsal sensory branch of the radial nerve and medial antebrachial cutaneous nerve. The constant findings were the branches departing from the ulnar side of the posterior interosseous nerve and from the radial side, with an exception seen in 2 cases. A communicans branch between the posterior interosseous nerve and medial antebrachial cutaneous nerve was seen in all the specimens. The posterior interosseous nerve innervation extended beyond the level of the carpometacarpal joints II-V. The modified Sihler's staining technique allows for transparent visibility of the nerves that innervate the dorsal wrist capsule. However, it does not allow as accurate assessment as does histological examination, especially regarding the evaluation of nerve endings. Nevertheless, this method provides a significantly larger area of nerve observation than is provided by histological examination.

A STUDY OF CLINICAL PRESENTATION AND MANAGEMENT OF PITUITARY TUMORS

The study includes 25 cases of pituitary adenomas. Most common age group by pituitary tumors falls between 41-50 years of age. Male: Female incidence of these tumors is 1: 2.12. Most common clinical symptoms in our series are visual disturbances followed by headache. Optic nerve involvement is other common clinical nding presenting in form of decreased vision or loss of vision, eld defect or fundus changes. Commonest eld defect is bitemporal hemianopia. MRI is the diagnostic investigation of choice in pituitary tumors to dene extent, invasion and relationship to major vessels and nerves. Approximately half (44%) of the patients exhibited normal preoperative pituitary function in form of baseline hormone prole. Increased GH level (32%) followed by hyperprolactinemia (20%) are the most common endocrinologic abnormalities. Total/near total removal was done in 21 patients (84%) and subtotal removal done in 4 patients (16%). Adjuvant therapies were given in 5 patients. Two patients were given radiotherapy and 3 were given pharmacotherapy. Post operative complications were CSF leak, diabetes insipidus and meningitis. 20 patients (80%) had improvement in their symptoms including relief from headache, improvement in vision and endocrinal dysfunction. Post operatively visual functions improved in 13 patients (52%) and it remained stationary in 11 (44%) patients. Only one patient (4%) complained of worsening of his visual function and it was improved in follow up period

Soft tissue sarcoma of the upper extremity: oncological and functional results after surgery.

This retrospective study evaluates outcomes after treatment of upper-extremity soft tissue sarcoma in 44 patients. We re-resected 19 tumours that had been resected elsewhere without adequate preoperative planning, and we made 25 well-planned primary resections. Four patients in the unplanned group and five in the planned group eventually received amputations. Thirty-three patients were alive at a median follow-up time of 33months (IQR 18 to 57). Tumour size > 7 cm, tumour Grade 3 and the presence of distant organ metastases were the main factors affecting the oncological outcomes. We found no statistical differences between the planning groups. Functional outcomes and quality of life were significantly worse after amputation or major nerve resections. We conclude with this sized sample that the lack of planning in itself did not influence the final results, but there were differences in tumour size, grade and localization between the groups that may play a role.Level of evidence: IV.

Brachytherapy of the head and neck: An University of California Los Angeles guide to morbidity reduction

The head and neck (H&N) region is among the most intricate and functional part of our anatomy. Major functional nerves and blood vessels with importance that affect the entire body emanate from the base of skull. Brachytherapy plays an important role as a single modality therapy in early cancer of the lip and oral cavity and a supplemental role in the pharynx or in advanced or recurrent disease. Morbidity in the H&N is intensely personal and disabling. Its avoidance is critical in determining the success or failure of a treatment program, and it is essential to preservation of quality of life. This article summarizes the current literature regarding morbidity related to H&N brachytherapy to aid patients and physicians to achieve optimal outcomes.

ROLE OF MANIPUR CHAKRA ACTIVATION IN TREATMENT OF DIABETES MELLITUS

Chakras are the circular vortex of energy lying across the seven different points on your spinal column. On a physical level, chakras are associated with the major nerve plexuses and endocrine glands in the body. Many asanas have particularly powerful and beneficial effect on one or more of these glands or plexuses. Chakras are not the physical entity and reside in energy body, but help us to understand the body functions and emotions. As they are psychoactive energy centers in human body they are directly related to physiological and psychological health of human being. The unavoidable stress in lifestyle has blocked the entire chakra system and imbalance in the energy flow causes various diseases. We have the great ancient knowledge with us to regulate the energy flow through chakras and get cured from various disorders related to that chakra. Mechanism of yoga effects is the most visible in the systems of chakras and nadis, which specifically and directly correlates with nervous and endocrine system. This study is a small effort to prove the effect and application of Manipur chakra activation in management of life style disorders especially diabetes mellitus.

Clinical experience of extreme lateral interbody fusion in the treatment of lumbar spondylodiscitis

Introduction Up to now, there were few studies on extreme lateral interbody fusion (XLIF) surgery for lumbar spondylodiscitis. This study was aimed to evaluate clinical effectiveness and provide more information for XLIF in the treatment of lumbar spondylodiscitis. Methods We retrospectively collected cases of XLIF for the treatment of lumbar spondylodiscitis from September 2017 to February 2020. There were 8 cases of non-specific infection of lumbar spine, 4 cases of lumbar tuberculosis, and 1 case of lumbar brucellosis. Basic information, antibiotic application, and inflammatory index were collected before and after surgery. Clinical effectiveness was evaluated at baseline and in 3, 6, and 12 months after the surgery with visual analog scale (VAS) and Oswestry disability index (ODI). The comparison of the indicators before and after the operation was performed by repeated measures analysis of variance. Results The average intraoperative blood loss and operation time was 70mL and 99.23 min, respectively. The study consisted of 13 cases with single segment operation. The average follow-up time was 16.54 months. No sign of recurrence of spondylodiscitis occurred at last follow-up. Postoperative VAS and ODI were significantly decreased after the operation. No major blood vessels, nerves, or organ damage occurred during the perioperative period. Conclusion XLIF has shown good clinical effectiveness in the treatment of lumbar spondylodiscitis with advantages of less bleeding and less tissue damage in the present study. More multi-center prospective comparative studies are needed to further verify the clinical effectiveness of this procedure in lumbar spondylodiscitis.

Biopreservation of living tissue engineered nerve grafts

Tissue engineered nerve grafts (TENGs) built from living neurons and aligned axon tracts offer a revolutionary new approach as “living scaffolds” to bridge major peripheral nerve defects. Clinical application, however, necessitates sufficient shelf-life to allow for shipping from manufacturing facility to clinic as well as storage until use. Here, hypothermic storage in commercially available hibernation media is explored as a potential biopreservation strategy for TENGs. After up to 28 days of refrigeration at 4℃, TENGs maintain viability and structure in vitro. Following transplantation into 1 cm rat sciatic defects, biopreserved TENGs routinely survive and persist for at least 2 weeks and recapitulate pro-regenerative mechanisms of fresh TENGs, including the ability to recruit regenerating host tissue into the graft and extend neurites beyond the margins of the graft. The protocols and timelines established here serve as important foundational work for the manufacturing, storage, and translation of other neuron-based tissue engineered therapeutics.

Local continuous glial cell derived neurotrophic factor release using osmotic pump promotes parasympathetic nerve rehabilitation in an animal model of cavernous nerve injury induced erectile dysfunction.

BackgroundNerve injury-related erectile dysfunction (ED) is one of the types that respond poorly to conventional ED treatments. Our previous experiments have demonstrated the paracrine of various neurotrophic factors (NTFs) by stem cells or other treatment modalities as a potential mechanism in the recovery of nerve injury-related ED. Glial cell derived neurotrophic factor (GDNF) is one of the essential NTFs for the regeneration of nerve fibers, especially for parasympathetic nerves. The aim of this study is to explore if local continuous GDNF administration is beneficial for the functional and histological recovery of nerve injury induced ED.MethodsEight-week-old male Sprague-Dawley rats were used for this study. Rats were randomly grouped into 5: Sham surgery (Sham), bilateral cavernous nerve injury (BCNI) and placebo treatment, BCNI and 0.1 µg/100 µL GDNF treatment (BCNI+GDNF 0.1), BCNI and 1 µg/100 µL GDNF treatment (BCNI+GDNF 1), BCNI and 10 µg/100 µL GDNF treatment (BCNI+GDNF 10). GDNF was administered using an osmotic pump technique which would deliver GDNF locally and continuously for 28 days without the need for external connections or frequent handling of animals. Recovery of sexual function, nerve fibers regeneration, and expression of neurotrophic receptors were examined and compared among groups after the treatment.ResultsLocal continuous GDNF release treatment increased the average number of intromissions in the sexual behavior test and intracavernous pressure (ICP) in the erectile function test in a dose dependent manner. Osmotic pump implantation induced increased local GDNF concentration and mild inflammatory response. Gene expression of GDNF receptors in major pelvic ganglion (MPG) and nerve regeneration along the urethra were partially promoted by GDNF. These changes were associated with increased nerve fibers especially the parasympathetic nerve fibers in dorsal nerve of penis (DNP) in GDNF treated groups.ConclusionsIn conclusion, our project illustrated the promising effects of local continuous GDNF administration for the functional and histological recovery of nerve injury-induced ED.

Supraretinacular endoscopic carpal tunnel release: A safe alternative method for treatment of carpal tunnel syndrome.

Supraretinacular endoscopic carpal tunnel release (SRECTR) is a technique in which an endoscope is inserted superficial to the flexor retinaculum through a subcutaneous tunnel. The benefits of this method include a clear view for the surgeon and absence of median nerve compression. Surgeons can operate with a familiar view of the flexor retinaculum and median nerve downward, similar to open surgery. This study aimed to investigate the learning curve for SRECTR, an alternate method for carpal tunnel release, and evaluate its complications and the functional outcomes using a disposable commercial kit. We examined the open conversion rates and complications associated with SRECTR in 200 consecutive patients performed by two surgeons. We compared the operative time operated by a single surgeon. We evaluated outcomes in 191 patients according to Kelly's grading system. Patients' mean follow-up period was 12.7 months. Nine patients required conversion to open surgery. There were no injuries to the nerves and tendons and no hematoma or incomplete dissection of the flexor retinaculum. The operative times varied between 11 and 34 minutes. We obtained the following results based on Kelly's grading of outcomes: excellent in 116, good in 59, fair in 13, and poor in 3 patients. We found no patients with neurapraxia, major nerve injury, flexor tendon injury, superficial palmar arch injury, and hematoma. Although there was a learning curve associated with SRECTR, we performed 200 consecutive cases without neurovascular complications. This method may be a safe alternative to minimally invasive carpal tunnel surgery.

Cytomorphological Patterns of Nerve Aspirates in Pure Neuritic Leprosy-A Single Centre Cross-Sectional Observational Study.

Background:Pure neuritic leprosy (PNL) poses a diagnostic challenge because of absence of skin patches, inconclusive skin biopsies and nerve conduction studies. Nerve biopsy though the diagnostic gold standard, is invasive, requires expertise, and may not be feasible in all cases. Fine needle aspiration cytology (FNAC) of accessible thickened nerves can be utilized as a minimally invasive diagnostic modality in PNL. This study was carried out to describe cytomorphological patterns of nerve aspirates in patients of PNL for diagnosis and classification of leprosy and study its advantage, if any, over skin biopsy.Methods:Twenty-seven treatment naive clinically diagnosed patients of PNL were included in this cross-sectional study carried out from January 2017 to December 2018 at a tertiary care centre in Western India. FNAC was done from a clinically involved nerve and aspirates were evaluated for cytomorphological characteristics and the presence of Acid-Fast Lepra bacilli.Results:Nerve aspirates were diagnostic in 10 (37%) patients while 17 (63%) aspirates showed non-specific or no inflammation. Of the diagnostic aspirates, six (22.2%) were classified as tuberculoid leprosy, three (11.1%) as lepromatous and one (3.7%) as borderline leprosy. Mycobacterium leprae were demonstrated among three (11.1%) of these aspirates. In comparison, only three (11.1%) skin biopsies were diagnostic of leprosy with features of indeterminate spectrum. Remaining 24 skin biopsies showed normal histology in 20 (74.1%) cases to perivascular lymphocytic infiltrate in four (14.8%) cases.Conclusion:Our study demonstrates that FNAC of clinically thickened nerves has a better diagnostic yield than skin biopsy in PNL and shows all spectrums of leprosy. It also offers the advantage of sampling major nerve trunks without the fear of residual neurological deficit. However, most of the smears were paucicellular and a negative aspirate does not rule out leprosy.

Schwannoma in the extremity: clinical features and microscopic intra-capsular enucleation.

Objective: Schwannomas are the most common type of neoplasm of the peripheral nerves. Enucleation is a standard surgical procedure; however, it occasionally results in iatrogenic nerve injury, even with atraumatic procedures. Herein, we present the clinical characteristics of schwannoma arising in the extremities and discuss the clinical outcomes of extra- and intra-capsular enucleation.Patients and Methods: We reviewed 122 schwannomas treated at our institute. Schwannomas arising from the minor nerve (n=30) or intramuscularly (n=15) were operated using the extra-capsular technique. Of the 77 major nerve schwannomas, 62 schwannomas were treated using the intra-capsular technique and 15 schwannomas using the extra-capsular technique.Results: Neurological deficits following enucleation were significantly lower using the intra-capsular technique than with the extra-capsular technique. The patient age, duration of symptoms, maximum tumor diameter, and site of occurrence were not associated with subsequent neurological deficits. With both techniques, no tumor recurrence was observed at the final follow-up.Conclusion: These results support the use of intra-capsular micro-enucleation as a safe and reliable treatment for every type of schwannoma. To minimize the risk of nerve injury, en bloc resection should not be used because the main purpose of schwannoma surgery is the relief of symptoms, not tumor resection.

Retrospective review of complications following long tourniquet time in foot and ankle surgery

BackgroundTourniquet use is ubiquitous in orthopaedic surgery to create a bloodless field and to facilitate safe surgery, however, we know of the potential complications that can occur as a result of prolonged tourniquet time. Experimental and clinical research has helped define the safe time limits but there is not much literature specific to foot and ankle surgery. MethodsA retrospective review of the postoperative course of patients with prolonged tourniquet time (longer than 180 min) for foot and ankle procedures was done. Data related to the patient factors and the surgical procedure was collected. The length of stay, re-admissions and complications were the important indicators of the individual patient’s recovery. ResultsTwenty patients were identified with longer than 180-min tourniquet times for complex foot and ankle procedures. The average uninterrupted tourniquet time was 191 min. Eight of the twenty procedures were revision surgeries. The average length of stay was 3 days and there were no re-admissions within 30 days. Eight patients (40%) had at least one recorded complication. The complications seen in this group were transient sensory loss, wound issues, superficial infection, ongoing pain and non-union. ConclusionsThis case series has not revealed any major systemic complications resulting from the prolonged tourniquet such as pulmonary embolism or renal dysfunction. Unlike past literature on knee procedures with extended tourniquet times, no major nerve palsies were seen in our patient group. Our understanding of the local and systemic effects of tourniquet is not complete and this study demonstrates that the complications do not necessarily increase in a linear fashion in relation to the tourniquet time.

A Neuroskeletal Atlas: Spatial Mapping and Contextualization of Axon Subtypes Innervating the Long Bones of C3H and B6 Mice.

ABSTRACTNerves in bone play well‐established roles in pain and vasoregulation and have been associated with progression of skeletal disorders, including osteoporosis, fracture, arthritis, and tumor metastasis. However, isolation of the region‐specific mechanisms underlying these relationships is limited by our lack of quantitative methods for neuroskeletal analysis and precise maps of skeletal innervation. To overcome these limitations, we developed an optimized workflow for imaging and quantitative analysis of axons in and around the bone, including validation of Baf53b‐Cre in concert with R26R‐tdTomato (Ai9) as a robust pan‐neuronal reporter system for use in musculoskeletal tissues. In addition, we created comprehensive maps of sympathetic adrenergic and sensory peptidergic axons within and around the full length of the femur and tibia in two strains of mice (B6 and C3H). In the periosteum, these maps were related to the surrounding musculature, including entheses and myotendinous attachments to bone. Three distinct patterns of periosteal innervation (termed type I, II, III) were defined at sites that are important for bone pain, bone repair, and skeletal homeostasis. For the first time, our results establish a gradient of bone marrow axon density that increases from proximal to distal along the length of the tibia and define key regions of interest for neuroskeletal studies. Lastly, this information was related to major nerve branches and local maps of specialized mechanoreceptors. This detailed mapping and contextualization of the axonal subtypes innervating the skeleton is intended to serve as a guide during the design, implementation, and interpretation of future neuroskeletal studies and was compiled as a resource for the field as part of the NIH SPARC consortium. © 2021 The Authors. Journal of Bone and Mineral Research published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research (ASBMR)..

A minimally invasive periacetabular osteotomy technique: minimizing intraoperative risks.

The periacetabular osteotomy (PAO) is an extensive surgical procedure associated with potential risk to the adjacent neurovascular structures. A steep learning curve exists, with surgeon experience an important factor in outcome. Little detail exists of the osteotomies themselves, and how to make them safe and reproducible. This article describes our PAO technique with emphasis on specific safety steps. When performing the posterior column cut, migration of the osteotome beyond the lateral pelvis may lead to damage of the sciatic nerve. The safety features detailed include novel measurement of the posterior column width and the use of specific-width osteotomes to complete this osteotomy. To plan the cut, several computerized tomography-based measurements are taken starting just above the greater sciatic notch and continuing down to the inferior part of the acetabulum. The angle of this cut is determined by acetabular morphology and the width of the posterior column. These posterior column width measurements will determine the width of the osteotomes used to perform the cut with little risk that an osteotome will penetrate too far on the lateral side of the pelvis. To ensure the lateral cortex has been cut completely proximally, an osteotome with pre-measured depths may be used from a medial to a direct lateral trajectory. The senior author has been performing this modified approach since 2010 (n = 530 PAOs) and has witnessed no vascular injuries and no nerve injuries aside from minor lateral femoral cutaneous nerve issues. Utilization of these techniques has prevented any major nerve injury without the need for intraoperative electromyography.

Evidence for the cholinergic markers ChAT and vAChT in sensory cells of the developing antennal nervous system of the desert locust Schistocerca gregaria

Sensory and motor systems in insects with hemimetabolous development must be ready to mediate adaptive behavior directly on hatching from the egg. For the desert locust S. gregaria, cholinergic transmission from antennal sensillae to olfactory or mechanosensory centers in the brain requires that choline acetyltransferase (ChAT) and the vesicular acetylcholine transporter (vAChT) already be present in sensory cells in the first instar. In this study, we used immunolabeling to demonstrate that ChAT and vAChT are both expressed in sensory cells from identifiable sensilla types in the immature antennal nervous system. We observed ChAT expression in dendrites, neurites and somata of putative basiconic-type sensillae at the first instar stage. We also detected vAChT in the sensory axons of these sensillae in a major antennal nerve tract. We then examined whether evidence for cholinergic transmission is present during embryogenesis. Immunolabeling confirms that vAChT is expressed in somata typical of campaniform sensillae, as well as in small sensory cell clusters typically associated with either a large basiconic or coeloconic sensilla, at 99% of embryogenesis. The vAChT is also expressed in the somata of these sensilla types in multiple antennal regions at 90% of embryogenesis, but not at earlier (70%) embryonic stages. Neuromodulators are known to appear late in embryogenesis in neurons of the locust central complex, and the cholinergic system of the antenna may also only reach maturity shortly before hatching.

Incidence of peripheral nerve injury in revision total shoulder arthroplasty: an intraoperative nerve monitoring study

The incidence of nerve injuries in revision total shoulder arthroplasty (TSA) is not well defined in the literature and may be higher than that in primary procedures, with 1 study reporting a complication rate of 50% for shoulder revisions. Given that continuous intraoperative nerve monitoring (IONM) can be an effective tool in diagnosing evolving neurologic dysfunction and preventing postoperative injuries, the purpose of this study was to report on IONM data and nerve injury rates in a series of revision TSAs. A retrospective cohort review of consecutive patients who underwent revision TSA was performed from January 2016 to March 2020. Indications for revision included infection (n = 7); failed total arthroplasty and hemiarthroplasty secondary to pain, dysfunction, and/or loose components (n = 36); and periprosthetic fracture (n = 1). Of the shoulders, 32 underwent revision to a reverse TSA, 6 underwent revision to an anatomic TSA, and 6 underwent spacer placement. IONM data included transcranial electrical motor evoked potentials (MEPs), somatosensory evoked potentials, and free-run electromyography. The motor alert threshold was set at ≥80% signal attenuation in any peripheral nerve. Patients were screened for neurologic deficits immediately following surgery, prior to administration of an interscalene nerve block, and during the first 2 postoperative visits. Additional data collection included surgical indication, sex, laterality, age at surgery, procedure performed, body mass index, history of tobacco use, Charlson Comorbidity Index, medical history, and preoperative range of motion. A total of 44 shoulders in 38 patients were included, with a mean age of 63.2 years (standard deviation, 13.0 years). Of the procedures, 22.4% (n = 10) had an MEP alert, with 8 isolated to a single nerve (7 axillary and 1 radial) and 1 isolated to the axillary and musculocutaneous nerves. Only 1 patient experienced a major brachial plexus alert involving axillary, musculocutaneous, radial, ulnar, and median nerve MEP alerts, as well as ulnar and median nerve somatosensory evoked potential alerts. Age, sex, body mass index, Charlson Comorbidity Index, and preoperative range of motion were not found to be significantly different between cases in which an MEP alert occurred and cases with no MEP alerts. In the postoperative period, no minor or major nerve injuries were found whereas distal peripheral neuropathy developed in 4 patients (9.1%). Among 44 surgical procedures, no patients (0%) had a major or minor nerve injury postoperatively and 4 patients (9.1%) complained of distal peripheral neuropathy postoperatively. In this study, we have shown that through the use of IONM, the rate of minor and major nerve injuries can be minimized in revision shoulder arthroplasty.

Anatomic versus reverse shoulder arthroplasty, are nerve injury rates different?

BackgroundThe true incidence of iatrogenic neurological injury following total shoulder arthroplasty (TSA) surgery remains controversial at a cited rate of 1%-18.7%. Additionally, there is a reported incidence of new onset distal peripheral neuropathy (DPN) of 7.1% and 12.3%, for anatomic (aTSA) and reverse (rTSA) shoulder replacements, respectively. The purpose of this present study is to report on nerve injury rates of a large, consecutive series of primary TSA (ie, rTSA and aTSA) performed by one surgeon, utilizing intraoperative neuromonitoring and consistent implant design. MethodsA retrospective cohort review of consecutive patients who underwent primary TSA was performed from January 2016 to March 2020. Intraoperative neuromonitoring data included transcranial electrical motor evoked potentials (MEPs), somatosensory evoked potentials, and free-run electromyography. Motor alert threshold was set at ≥ 80% signal attenuation in any one or more peripheral nerves. Patients were screened for neurological deficits immediately following surgery and in the first 2 postoperative visits. Additional data collection included surgical indication, gender, laterality, age at surgery, procedure performed, body mass index, history of tobacco use, Charlson comorbidity index, past medical history and preoperative range of motion. ResultsA total of 290 consecutive shoulders in 270 patients were included. Ninety-one (31.4%) shoulders underwent aTSA, while 199 (68.6%) underwent rTSA. Patients in the rTSA cohort were significantly older (70.1 vs. 61.3 years; P < .001), had higher Charlson comorbidity index scores (4.3 vs. 3.0; P < .001), and shorter operative time (81.8 vs. 99.7; P < .001). A total of 96 MEP alerts occurred in 65 (22.4%) operations, with a significantly higher proportion of these occurring in patients undergoing aTSA. MEP alerts occurred in 28 (39.8%) aTSA versus 37 (18.5%) rTSA (P = .024). Logistical regression found operative time (P = .003, odds ratio = 1.020 [95%: 1.007-1.033]) was predictive of a MEP alert. The axillary nerve was the most commonly alerted nerve accounting for 61.5% of all alerts. Zero patients had a major or minor nerve injury in this large cohort. Nine patients (3.1%) had DPN in the postoperative period. ConclusionIn 290 surgeries, no (0%) patients had a postoperative major or minor nerve injury, and 9 (3.1%) patients complained of postoperative distal peripheral neuropathy. Patients that had MEP alerts had significantly longer operative times and were more likely to be in the aTSA group compared to the rTSA group. This may be attributed to longer exposure and implantation times on the glenoid side for an anatomic as opposed to a reverse arthroplasty. Level of evidenceLevel III; Retrospective Cohort study.

Deep learning the sound of light to guide surgeries

Photoacoustic imaging utilizes light and sound to make images by transmitting laser pulses that illuminate regions of interest, which subsequently absorb the light, causing thermal expansion and the generation of sound waves that are detected with conventional ultrasound transducers. The Photoacoustic and Ultrasonic Systems Engineering (PULSE) Lab is developing novel methods that use photoacoustic imaging to guide surgeries with the ultimate goal of eliminating surgical complications caused by injury to important structures like major blood vessels and nerves that are otherwise hidden from a surgeons immediate view. This invited presentation will summarize our recent work to learn from the physics of sound propagation in tissue and develop acoustic beamforming algorithms that improve image quality, using state-of-the-art deep learning methods. These deep learning methods hold promise for robotic tracking tasks, visualization and visual servoing of surgical tool tips, and assessment of relative distances between the surgical tool and nearby critical structures (e.g., major blood vessels and nerves that if injured will cause severe complications, paralysis, or patient death). Impacted surgeries and procedures include neurosurgery, spinal fusion surgery, hysterectomies, cardiac interventions, and biopsies.