Awake spinal surgery: simplifying the learning curve with a patient selection algorithm.

OBJECTIVE: There is a learning curve for surgeons performing "awake" spinal surgery. No comprehensive guidelines have been proposed for the selection of ideal candidates for awake spinal fusion or decompression. The authors sought to formulate an algorithm to aid in patient selection for surgeons who are in the startup phase of awake spinal surgery. METHODS: The authors developed an algorithm for selecting patients appropriate for awake spinal fusion or decompression using spinal anesthesia supplemented with mild sedation and local analgesia. The anesthetic protocol that was used has previously been reported in the literature. This algorithm was formulated based on a multidisciplinary team meeting and used in the first 15 patients who underwent awake lumbar surgery at a single institution. RESULTS: A total of 15 patients who underwent decompression or lumbar fusion using the awake protocol were reviewed. The mean patient age was 61 ± 12 years, with a median BMI of 25.3 (IQR 2.7) and a mean Charlson Comorbidity Index of 2.1 ± 1.7; 7 patients (47%) were female. Key patient inclusion criteria were no history of anxiety, 1 to 2 levels of lumbar pathology, moderate stenosis and/or grade I spondylolisthesis, and no prior lumbar surgery at the level where the needle is introduced for anesthesia. Key exclusion criteria included severe and critical central canal stenosis or patients who did not meet the inclusion criteria. Using the novel algorithm, 14 patients (93%) successfully underwent awake spinal surgery without conversion to general anesthesia. One patient (7%) was converted to general anesthesia due to insufficient analgesia from spinal anesthesia. Overall, 93% (n = 14) of the patients were assessed as American Society of Anesthesiologists class II, with 1 patient (7%) as class III. The mean operative time was 115 minutes (± 60 minutes) with a mean estimated blood loss of 46 ± 39 mL. The median hospital length of stay was 1.3 days (IQR 0.1 days). No patients developed postoperative complications and only 1 patient (7%) required reoperation. The mean Oswestry Disability Index score decreased following operative intervention by 5.1 ± 10.8. CONCLUSIONS: The authors propose an easy-to-use patient selection algorithm with the aim of assisting surgeons with patient selection for awake spinal surgery while considering BMI, patient anxiety, levels of surgery, and the extent of stenosis. The algorithm is specifically intended to assist surgeons who are in the learning curve of their first awake spinal surgery cases.

Safe and successful resection of difficult GI lesions using a novel single-step full-thickness resection device (FTRD®).

BACKGROUND AND STUDY AIMS: Classic endoscopic resection techniques (EMR and ESD) are limited to mucosal lesions. In the case of deeper growth into the gut wall and anatomic sites prone to perforation, the novel full-thickness resection device (FTRD®) opens a new dimension of possibilities for endoscopic resection. PATIENTS AND METHODS: Sixty patients underwent endoscopic full-thickness resection (eFTR) at our institution. Safety, learning curve, R0 resection rate, and clinical outcome were studied. RESULTS: In 97% (58/60) of the interventions, the FTRD®-mounted endoscope reached the previously marked lesion and eFTR was performed (technical success). Full-thickness resection was achieved in 88% of the cases, with an R0 resection on histological examination in 79%. The clinical success rate based on follow-up histology was even higher (88%). Adverse events occurred in 7%. Appendicitis of the residual cecal appendix after eFTR of an adenoma arising in the appendix led to the only post-eFTR surgery (1/58, 2%). Minor bleeding at the eFTR site (2/58, 3%) and an eFTR performed accidently without proper prior deployment of the OTSC® (1/58, 2%) were successfully treated endoscopically. There was no secondary perforation or eFTR-associated mortality. CONCLUSIONS: After specific training, eFTR is a feasible, safe, and promising all-in-one endoscopic resection technique. Our data show that eFTR allows complete resection of lesions affecting layers of the gut wall beneath the mucosa with a low risk of adverse events. However, our preliminary results need to be confirmed in larger, controlled studies.

Chest CT Image based Lung Disease Classification - A Review.

Computed tomography (CT) scans are widely used to diagnose lung conditions due to their ability to provide a detailed overview of the body's respiratory system. Despite its popularity, visual examination of CT scan images can lead to misinterpretations that impede a timely diagnosis. Utilizing technology to evaluate images for disease detection is also a challenge. As a result, there is a significant demand for more advanced systems that can accurately classify lung diseases from CT scan images. In this work, we provide an extensive analysis of different approaches and their performances that can help young researchers to build more advanced systems. First, we briefly introduce diagnosis and treatment procedures for various lung diseases. Then, a brief description of existing methods used for the classification of lung diseases is presented. Later, an overview of the general procedures for lung disease classification using machine learning (ML) is provided. Furthermore, an overview of recent progress in ML-based classification of lung diseases is provided. Finally, existing challenges in ML techniques are presented. It is concluded that deep learning techniques have revolutionized the early identification of lung disorders. We expect that this work will equip medical professionals with the awareness they require in order to recognize and classify certain medical disorders.

The design, development, and implementation of a checklist for intraoperative neuromonitoring changes.

OBJECT: The purpose of this study was to provide an evidence-based algorithm for the design, development, and implementation of a new checklist for the response to an intraoperative neuromonitoring alert during spine surgery. METHODS: The aviation and surgical literature was surveyed for evidence of successful checklist design, development, and implementation. The limitations of checklists and the barriers to their implementation were reviewed. Based on this review, an algorithm for neurosurgical checklist creation and implementation was developed. Using this algorithm, a multidisciplinary team surveyed the literature for the best practices for how to respond to an intraoperative neuromonitoring alert. All stakeholders then reviewed the evidence and came to consensus regarding items for inclusion in the checklist. RESULTS: A checklist for responding to an intraoperative neuromonitoring alert was devised. It highlights the specific roles of the anesthesiologist, surgeon, and neuromonitoring personnel and encourages communication between teams. It focuses on the items critical for identifying and correcting reversible causes of neuromonitoring alerts. Following initial design, the checklist draft was reviewed and amended with stakeholder input. The checklist was then evaluated in a small-scale trial and revised based on usability and feasibility. CONCLUSIONS: The authors have developed an evidence-based algorithm for the design, development, and implementation of checklists in neurosurgery and have used this algorithm to devise a checklist for responding to intraoperative neuromonitoring alerts in spine surgery.

Consensus-based perioperative protocols during the COVID-19 pandemic.

OBJECTIVE: During the COVID-19 pandemic, quaternary-care facilities continue to provide care for patients in need of urgent and emergent invasive procedures. Perioperative protocols are needed to streamline care for these patients notwithstanding capacity and resource constraints. METHODS: A multidisciplinary panel was assembled at the University of California, San Francisco, with 26 leaders across 10 academic departments, including 7 department chairpersons, the chief medical officer, the chief operating officer, infection control officers, nursing leaders, and resident house staff champions. An epidemiologist, an ethicist, and a statistician were also consulted. A modified two-round, blinded Delphi method based on 18 agree/disagree statements was used to build consensus. Significant disagreement for each statement was tested using a one-sided exact binomial test against an expected outcome of 95% consensus using a significance threshold of p < 0.05. Final triage protocols were developed with unblinded group-level discussion. RESULTS: Overall, 15 of 18 statements achieved consensus in the first round of the Delphi method; the 3 statements with significant disagreement (p < 0.01) were modified and iteratively resubmitted to the expert panel to achieve consensus. Consensus-based protocols were developed using unblinded multidisciplinary panel discussions. The final algorithms 1) quantified outbreak level, 2) triaged patients based on acuity, 3) provided a checklist for urgent/emergent invasive procedures, and 4) created a novel scoring system for the allocation of personal protective equipment. In particular, the authors modified the American College of Surgeons three-tiered triage system to incorporate more urgent cases, as are often encountered in neurosurgery and spine surgery. CONCLUSIONS: Urgent and emergent invasive procedures need to be performed during the COVID-19 pandemic. The consensus-based protocols in this study may assist healthcare providers to optimize perioperative care during the pandemic.

Neuroanesthesia Guidelines for Optimizing Transcranial Motor Evoked Potential Neuromonitoring During Deformity and Complex Spinal Surgery: A Delphi Consensus Study.

STUDY DESIGN: Expert opinion-modified Delphi study. OBJECTIVE: We used a modified Delphi approach to obtain consensus among leading spinal deformity surgeons and their neuroanesthesiology teams regarding optimal practices for obtaining reliable motor evoked potential (MEP) signals. SUMMARY OF BACKGROUND DATA: Intraoperative neurophysiological monitoring of transcranial MEPs provides the best method for assessing spinal cord integrity during complex spinal surgeries. MEPs are affected by pharmacological and physiological parameters. It is the responsibility of the spine surgeon and neuroanesthesia team to understand how they can best maintain high-quality MEP signals throughout surgery. Nevertheless, varying approaches to neuroanesthesia are seen in clinical practice. METHODS: We identified 19 international expert spinal deformity treatment teams. A modified Delphi process with two rounds of surveying was performed. Greater than 50% agreement on the final statements was considered "agreement"; >75% agreement was considered "consensus." RESULTS: Anesthesia regimens and protocols were obtained from the expert centers. There was a large amount of variability among centers. Two rounds of consensus surveying were performed, and all centers participated in both rounds of surveying. Consensus was obtained for 12 of 15 statements, and majority agreement was obtained for two of the remaining statements. Total intravenous anesthesia was identified as the preferred method of maintenance, with few centers allowing for low mean alveolar concentration of inhaled anesthetic. Most centers advocated for <150 µg/kg/min of propofol with titration to the lowest dose that maintains appropriate anesthesia depth based on awareness monitoring. Use of adjuvant intravenous anesthetics, including ketamine, low-dose dexmedetomidine, and lidocaine, may help to reduce propofol requirements without negatively effecting MEP signals. CONCLUSION: Spine surgeons and neuroanesthesia teams should be familiar with methods for optimizing MEPs during deformity and complex spinal cases. Although variability in practices exists, there is consensus among international spinal deformity treatment centers regarding best practices. LEVEL OF EVIDENCE: 5.

Changes of circulating antibody levels induced by ABO antibody adsorption for ABO-incompatible kidney transplantation.

ABO-incompatible kidney transplantation using immunoadsorption to remove anti-A/B antibodies has become a successful clinical practice. Since the data on the specificity of the ABO columns are controversial, the present study assessed the efficiency and specificity of the ABO immunoadsorption, the effect on total immunoglobulins and antibodies previously induced by vaccination. Anti-A/B antibodies were measured by agglutination and ABO flow cytometry, total IgG/IgM, carbohydrate- and protein-specific antibodies by nephelometry and ELISA. The first immunoadsorption not only efficiently reduced donor-specific anti-A/B IgM (81%) and IgG (56%) but also reduced compatible anti-A/B IgM (59%) and IgG (34%). The measurements of antidonor A/B antibodies by direct agglutination (IgM) or flow cytometry better represented the effective antibody levels than the indirect agglutination test (IgG). The median reduction of total IgM and total IgG levels after a single immunoadsorption was 34% and 18%, respectively. Antibodies against pneumococcus and haemophilus polysaccharide antigens were significantly reduced, whereas antitetanus and antidiphtheria protein antibodies were not affected. Intravenous immunoglobulin administration restored the protective anticarbohydrate antibody levels. In summary, immunoadsorption efficiently removed antidonor A/B antibodies, but was not specific for A/B antigens. Anti-A/B antibody levels as determined by ABO flow cytometry are useful to establish the minimal number of immunoadsorptions needed for successful ABO-incompatible transplantation.

Diagnostic use of endoscopic full-thickness wall resection (eFTR)-a novel minimally invasive technique for colonic tissue sampling in patients with severe gastrointestinal motility disorders.

BACKGROUND: Complex gastrointestinal (GI) motility disorders such as chronic intestinal pseudo-obstruction (CIPO) or Hirschsprung's disease (HD) are challenging to diagnose and treat appropriately. Thorough assessment of patient history, radiographic exams, endoscopy, and motility measurements aid in diagnostic workup, yet underlying histology is the cornerstone to enable a more distinct diagnosis of neuromuscular GI disorders. Traditionally, surgical procedures have been performed to obtain specimen suitable for accurate histologic analysis. METHODS: We performed endoscopic full-thickness resection (eFTR) using a full-thickness-resection device (FTRD) under moderate propofol sedation in four patients with suspected severe neuromuscular gut disorders including CIPO. KEY RESULTS: The mean age of the four patients was 43 y (range 19-56 y). Technical and histological success providing large colonic full-thickness tissue samples of excellent quality was achieved in all four patients (success rate 100%). The mean procedure time was 12 min (range 5-20 min). The mean diameter of the resected specimen was 21 mm (range 20-22 mm). No adverse events connected to the procedure itself occurred. Histology ranged from aganglionosis such as Hirschsprung's disease (HD) to hypoganglionosis and eosinophilic leiomyositis combined with lymphocytic ganglionitis in a third patient. Histology was unspecific in one patient. CONCLUSION AND INFERENCES: EFTR allows safe and minimal invasive harvesting of ample full-thickness tissue samples for accurate histological analysis in patients with suspicion of neuromuscular gut disorders.

Review article including treatment algorithm: endoscopic treatment of luminal complications after bariatric surgery.

The worldwide number of performed bariatric surgeries is increasing continuously, whereas laparoscopic Roux-en-Y gastric bypass (RYGB) and sleeve gastrectomy are conducted most frequently. Alongside with the usual post-operative and metabolic complications, luminal complications such as anastomotic bleeding, ulceration, leakage, fistula formation, enlargement and stenosis of the anastomosis may occur. Evolution of interventional endoscopy frequently allows endoscopic management of complications, avoiding surgical interventions in most cases. Here, we review the various luminal complications after bariatric surgery with a focus on their endoscopic management.

Establishment of Over-The-Scope-Clips (OTSC®) in daily endoscopic routine.

BACKGROUND: Alongside the evolution of interventional endoscopy, the need for a more sophisticated closure tool tailored to the treatment of new challenging indications has been increasing rapidly. METHODS: We here present our collected data on 262 Over-The-Scope-Clip (OTSC®) placements in a total of 233 interventions at our institution. Follow-up was focused on clinically lasting success with regards to different indications. RESULTS: Immediate success of OTSC® treatment was observed in 87.1% of all sessions (203/233). The success rates per indication were as follows: spontaneous bleeding 84.8% (28/33); iatrogenic bleeding 100% (20/20); acute perforation 90.3% (65/72); prophylaxis for perforation 100% (24/24); anastomotic leakage 61.1% (11/18); fistulae 80.7% (46/57); diameter reduction of the gastrojejunal anastomosis 100% (6/6); and stent fixation 100% (3/3). At 30-day follow-up, the overall success rate was 67.4% (157/233). The success rates per indication were as follows: spontaneous bleeding 69.7% (23/33); iatrogenic bleeding 90% (18/20); acute perforation 86.1% (62/72); prophylaxis for perforation 100% (24/24); anastomotic leakage 33.3% (6/18); fistulae 29.8% (17/57), diameter reduction of the gastrojejunal anastomosis 83.3% (5/6); and stent fixation 66% (2/3). CONCLUSIONS: Our cohort confirms previous data on the clinical usefulness of the OTSC® in daily routine practice.

Cervicothoracic kyphosis.

Cervicothoracic kyphotic deformity may inhibit horizontal gaze function, impede activities of daily living, and induce disabling pain. Eventually, some patients develop a chin-on-chest deformity that limits their ability to eat and drink; in the end stage, a few patients also may have difficulty breathing. Progressive kyphosis can stretch the spinal cord leading to myelopathy with progressive lower extremity spasticity and weakness. Indications for surgery include myelopathy, pain, dysphagia or dyspnea owing to kyphosis, and difficulty maintaining a functional horizontal gaze. Patients with unstable cervicothoracic fractures also require surgical fixation. For these patients, surgical goals include deformity correction with restoration of an acceptable forward gaze, re-establishment of sagittal balance, decompression of the spinal cord (if myelopathic), and stable fixation.

The vestibular hair cells: post-transductional signal processing.

Hair cells in mechanosensory systems transduce mechanical stimuli into biological signals to be presented to and analyzed by the brain. Vestibular hair cells transduce stimuli primarily associated with the organism's orientation and motion in space. When examined superficially it may appear that the hair cells act as passive transducers whereby mechanical stimulation of their hair bundle results in transmitter release at their afferent synapses. In fact, hair cell functions are more complicated, and the mechanical signals are heavily processed even before being encoded in afferent nerve activity. Hair cells are different from one another in morphology, biophysics, transmitter and transmitter receptor complements, not only across different organs (as one might expect), but even in the same organ. This review focuses on hair cell morpho-physiological properties, ionic conductances, neurotransmitters/modulators and their receptors, second messengers and effectors. Special features of hair cell neurotransmission, as the synaptic body and the presence of autoreceptors and local circuits, are also discussed, as is the possibility of a differential modulation of hair cell transmitter release in the resting and mechanically-stimulated states.

Inhibitory cerebellar circuits: GAD immunoreactivity in the frog cerebellum.

The presence of GABAergic structures in the frog cerebellum with simple nervous circuits was investigated with an immune serum raised against glutamic acid decarboxylase (GAD). GAD immunoreactivity is detectable in all the cerebellar layers. The most obvious difference in comparison with mammals is the scarcity of GAD-positive terminal boutons on Purkinje cells and this is consistent with neurophysiological data indicating that the inhibition on frog Purkinje cells is weaker than in mammals. However, there are numerous GAD synapses on cerebellar and vestibular nuclei. A large number of GAD immunoprecipitates are present in the molecular and granular layers, though their morphological organization is different from that in mammals. In the upper part of the molecular layer GAD immunoreactive cells and fibres form a plexus-like structure and in the internal granule layer immunoreactive varicosities are not arranged in the ring-like assemblies of mammals.

Mechanisms for sensory adaptation in frog vestibular organs.

The effects of external low-Ca, high-Mg solutions were tested both on frog isolated semicircular canals and on single cells isolated from these sensory organs. Our results showed that these media were able to cancel slow adaptation of the ampullar microphonic current in the whole organ and to abolish a Ca-dependent K current (IK(Ca)) in single hair cells, suggesting that IK(Ca) is involved in vestibular sensory adaptation.

NMDA receptors in frog semicircular canals.

The effects of competitive (2-amino-5-phosphonovaleric acid) and noncompetitive (Mg2+, ketamine and kynurenic acid) NMDA receptor antagonists were tested in isolated semicircular canals of the frog. All these antagonists reduced the resting firing rate recorded from the whole ampullar nerve of the posterior canal. This suggests that NMDA receptors are present at the cytoneural junctions between hair cells and afferent nerve terminals in frog vestibular organs.

Artifactual voltage response recorded from hair cells with patch-clamp amplifiers.

Patch-clamp amplifiers (PCAs) are commonly used to characterize voltage- and current-clamp responses in the same cell. However, the cell membrane voltage response can be severely distorted by PCAs working in the current-clamp mode. Here we compare the voltage response of pigeon semicircular canal hair cells in situ, recorded with two different PCAs, and with a classic microelectrode bridge amplifier (BA). We found that the voltage response of hair cells recorded with PCAs differed significantly from that recorded with the BA. The true hair cell membrane voltage response to positive current steps was characterized by a strongly damped oscillation, whose frequency and duration depended on hair cell location in the sensory crista ampullaris.

Calcium channels functional roles in the frog semicircular canal.

Different types of voltage-operated calcium channels have been described in hair cells; however, no clear functional role has been assigned to them. As a first functional characterization of vestibular calcium channels, we studied the effect of several calcium channel agonists and antagonists on whole nerve firing rate in an isolated frog semicircular canal preparation. Resting activity was affected by all dihydropyridines tested and by omegaconotoxin GVIA, whereas only nimodipine was able to reduce the mechanically evoked activity. These results indicate that nimodipine-sensitive channels play a major role in afferent transmitter release, and omega-conotoxin GVIA sensitive channels regulate the afferent firing (possibly on the postsynaptic side) but with a less important role.

beta amyloid-induced disruption of ionic balance: studies on the isolated frog labyrinth.

The beta-amyloid peptide (A beta) is a key player in the pathogenesis of Alzheimer's disease. Although its mechanisms of action are not fully elucidated, a disruption of ionic homeostasis has been suggested, and A beta aggregation in fibrils seems correlated to its toxic potential. In the present work, we studied the effects of different A beta fragments on the activity of frog ampullar nerve fibers. Our results show that A beta fragments are able to reduce ampullar nerve responses, with a potency correlated to their fibrillogenic capability. This study may have clinical implications, since vestibular problems are often reported in Alzheimer patients, and provide a model for the dissection of A beta effects in a simple multicomponent system.

Caloric stimulation of ampullar receptors: a new method to produce mechanically-evoked responses in frog semicircular canals.

A microthermistor positioned close to the exposed posterior semicircular canal in isolated labyrinth preparations of the frog was used to stimulate the sensory organ. Our results indicated that, depending on the position of the heater, the induced endolymphatic convection currents may result in either excitatory or inhibitory cupular deflections and thus in a modulation of ampullar receptor resting activity. Other possible thermal-dependent mechanisms, such as a direct action of the stimulus on vestibular sensors or endolymphatic volume changes, had, in the present experimental conditions, a minor role. Caloric stimulation could therefore represent a novel method to stimulate the semicircular canals 'in situ'.