The Use of Somatosensory Evoked Potentials to Determine the Relationship Between Intraoperative Arterial Blood Pressure and Intraoperative Upper Extremity Position–Related Neurapraxia in the Prone Surrender Position During Spine Surgery

Intraoperative somatosensory evoked potential (SEP) monitoring: an updated position statement by the American Society of Neurophysiological Monitoring

Somatosensory evoked potentials (SEPs) are used to assess the functional status of somatosensory pathways during surgical procedures and can help protect patients' neurological integrity intraoperatively. This is a position statement on intraoperative SEP monitoring from the American Society of Neurophysiological Monitoring (ASNM) and updates prior ASNM position statements on SEPs from the years 2005 and 2010. This position statement is endorsed by ASNM and serves as an educational service to the neurophysiological community on the recommended use of SEPs as a neurophysiological monitoring tool. It presents the rationale for SEP utilization and its clinical applications. It also covers the relevant anatomy, technical methodology for setup and signal acquisition, signal interpretation, anesthesia and physiological considerations, and documentation and credentialing requirements to optimize SEP monitoring to aid in protecting the nervous system during surgery.

Anesthetic Considerations for Patients with Hereditary Neuropathy with Liability to Pressure Palsies: A Narrative Review

Hereditary neuropathy with liability to pressure palsies (HNPP) is an autosomal dominant demyelinating neuropathy characterized by an increased susceptibility to peripheral nerve injury from trauma, compression, or shear forces. Patients with this condition are unique, necessitating distinct considerations for anesthesia and surgical teams. This review describes the etiology, prevalence, clinical presentation, and management of HNPP and presents contemporary evidence and recommendations for optimal care for HNPP patients in the perioperative period. While the incidence of HNPP is reported at 7-16:100,000, this figure may be an underestimation due to underdiagnosis, further complicating medicolegal issues. With the subtle nature of symptoms associated with HNPP, patients with this condition may remain unrecognized during the perioperative period, posing significant risks. Several aspects of caring for this population, including anesthetic choices, intraoperative positioning, and monitoring strategy, may deviate from standard practices. As such, a tailored approach to caring for this unique population, coupled with meticulous preoperative planning, is crucial and requires a multidisciplinary approach.

Intraoperative neurophysiologic monitoring prevented iatrogenic spinal cord injury during robotic-assisted transabdominal adrenalectomy: a case report

Cervical spondylotic myelopathy (CSM) is the most common disease of the cervical spinal cord in patients older than 55 and is characterized by an initial asymptomatic period followed by progressive neurological deficit from degenerative changes of the cervical vertebrae. These changes cause compression and vascular compromise to the cervical spinal cord. Because there are no pathognomonic symptoms, its diagnosis is commonly delayed. Herein we report the first case of the use of IONM during a transabdominal adrenalectomy in a patient with CSM, which prevented an iatrogenic spinal cord injury (SCI). The patient is a 74-year-old male with what was proven later as cervical spinal stenosis who presented for robotic-assisted transabdominal adrenalectomy. When positioned supine on the operating table, he exhibited upper and lower extremity neurological symptoms, prompting awake fiberoptic intubation and the use of IONM secondary to suspicion for CSM. After being positioned into lateral decubitus, IONM showed a loss of transcranial motor evoked potentials (TcMEP) and attenuated somatosensory evoked potentials (SSEP) from the right lower extremities and the procedure was aborted and the patient returned supine. TcMEPs returned to baseline, but SSEPs remained attenuated. The patient exhibited normal movement and sensation in post-anesthesia care. A high index of suspicion for CSM is required for older patients, as early diagnosis allows for spinal surgery treatment before acute worsening during anesthesia or non-spinal surgery. Furthermore, a low threshold for the use of IONM in patients with a high likelihood of CSM who require a non-spinal surgery can successfully prevent iatrogenic SCI.

Minimizing Blood Loss in Spine Surgery

STUDY DESIGN

Broad narrative review.

OBJECTIVE

To review and summarize the current literature on guidelines, outcomes, techniques and indications surrounding multiple modalities of minimizing blood loss in spine surgery.

METHODS

A thorough review of peer-reviewed literature was performed on the guidelines, outcomes, techniques, and indications for multiple modalities of minimizing blood loss in spine surgery.

RESULTS

There is a large body of literature that provides a consensus on guidelines regarding the appropriate timing of discontinuation of anticoagulation, aspirin, nonsteroidal anti-inflammatory drugs (NSAIDs), and herbal supplements prior to surgery. Additionally, there is a more heterogenous discussion the utility of preoperative autologous blood donation facilitated by erythropoietin and iron supplementation for healthy patients slated for procedures with high anticipated blood loss and for whom allogeneic transfusion is likely. Intraoperative maneuvers available to minimize blood loss include positioning and maintaining normothermia. Tranexamic acid (TXA), bipolar sealer electrocautery, and topical hemostatic agents, and hypotensive anesthesia (mean arterial pressure (MAP) <65 mm Hg) should be strongly considered in cases with larger exposures and higher anticipated blood loss. There is strong level 1 evidence for the use of TXA in spine surgery as it reduces the overall blood loss and transfusion requirements.

CONCLUSION

As the volume and complexity of spinal procedures rise, intraoperative blood loss management has become a pivotal topic of research within the field. There are many tools for minimizing blood loss in patients undergoing spine surgery. The current literature supports combining techniques to use a cost- effective multimodal approach to minimize blood loss in the perioperative period.

Cervical Cord Injury Following Posterior Spinal Fusion in a Patient With Adolescent Idiopathic Scoliosis: A Case Report

CASE

We present an 11-year-old girl with adolescent idiopathic scoliosis who underwent uncomplicated posterior spinal fusion and developed transient upper extremity weakness secondary to a cervical cord injury several hours after the conclusion of the case.

CONCLUSIONS

Perioperative hypotension, positioning, and mild cervical canal stenosis contributed to cervical cord injury following posterior thoracic instrumentation. Optimal perioperative resuscitation and awareness of cervical spine anatomy along with proper positioning may prevent this rare but potentially serious complication.

A Comprehensive Protocol to Prevent Brachial Plexus Injury During Ankylosing Spondylitis Surgery

PURPOSE

This article describes a comprehensive protocol to protect the brachial plexus when performing pedicle subtraction osteotomy for ankylosing spondylitis patients with thoracolumbar kyphosis.

DESIGN

A descriptive study was conducted.

METHODS

Records of 101 cases from October 2013 to December 2016 were retrospectively audited. The protocol included five items: (1) preoperative assessment of motion range and nerve function of limbs and trunks; (2) preoperative positioning according to the assessment results; (3) intra-operative somatosensory evoked potential and blood pressure monitoring; (4) intra-operative repositioning according to the monitoring alarm signals; and (5) postoperative neurological function check.

FINDINGS

Five patients showed impending brachial plexus injury indicators, including two who had a decrease in blood pressure and three who had a decrease in the amplitude of somatosensory evoked potential. After adjustment of position and soft pads, one patient had brachial plexus injury (0.99%) and the recovery time was 2 weeks.

CONCLUSIONS

With this comprehensive strategy, the brachial plexus could be effectively protected during the surgery.

Injury and Liability Associated With Spine Surgery

BACKGROUND

Although spine surgery is associated with significant morbidity, the anesthesia liability profile for spine surgery is not known. We examined claims for spine procedures in the Anesthesia Closed Claims Project database to evaluate patterns of injury and liability.

MATERIALS AND METHODS

A retrospective cohort study was performed. Inclusion criteria were anesthesia claims provided for surgical procedures in 2000 to 2014. We compared mechanisms of injury for cervical spine to thoracic or lumbar spine procedures using χ and the Fisher exact test. Univariate and multivariate logistic regression analyses were used to determine factors associated with permanent disabling injury in spine surgery claims.

RESULTS

The 207 spine procedure (73% thoracic/lumbar; 27% cervical) claims comprised >10% of claims. Permanent disabling injuries to nerves, the spinal cord, and the eyes or visual pathways were more common with spine procedures than in nonspine procedures. Hemorrhage and positioning injuries were more common in thoracic/lumbar spine claims, whereas difficult intubation was more common in cervical spine claims. Multiple logistic regression demonstrated prone positioning (odds ratio=3.50; 95% confidence interval, 1.30-9.43) and surgical duration of ≥4 hours increased the odds of severe permanent injury in spine claims (odds ratio=2.73; 95% confidence interval, 1.11-6.72).

CONCLUSIONS

Anesthesia claims related to spine surgery were associated with severe permanent disability primarily from nerve and eye injuries. Prone positioning and surgical duration of ≥4 hours were associated with permanent disabling injuries. Attention to positioning, resuscitation during blood loss, and reducing length of surgery may reduce these complications.

Risk factors for positioning-related somatosensory evoked potential changes in 3946 spinal surgeries

The goal of this study was to evaluate the risk factors associated with positioning-related SSEP changes (PRSC). The study investigated the association between 18 plausible risk factors and the occurrence of intraoperative PRSC. Risk factors investigated included demographic variables, comorbidities, and procedure related variables. All patients were treated by the University of Pittsburgh Medical Center from 2010 to 2012. We used univariate and multivariate statistical methods. 69 out of the 3946 (1.75%) spinal surgeries resulted in PRSC changes. The risk of PRSC was increased for women (p < 0.001), patients older than 65 years of age (p = 0.01), higher BMI (p < 0.001) patients, smokers (p < 0.001), and patients with hypertension (p < 0.001). No associations were found between PRSC and age greater than 80 years, diabetes mellitus, cardiovascular disease, and peripheral vascular disease. Three surgical situations were associated with PRSC including abnormal baselines (p < 0.001), patients in the "superman" position (p < 0.001), and patients in surgical procedures that extended over 200 min (p = 0.03). Patients with higher BMIs and who are undergoing spinal surgery longer than 200 min, with abnormal baselines, must be positioned with meticulous attention. Gender, hypertension, and smoking were also found to be risk factors from their odds ratios.

Bilateral position-related ulnar neuropathy at elbow in pediatric population and review of the literature

Perioperative ulnar neuropathies attributed to inappropriate arm positioning and padding during surgical procedures are commonly found in adults. However, their extremely rare incidence in the pediatric population may cause absent awareness of the risk of nerve injury in anesthetized pediatric patients. Furthermore, young patients respond to conservative treatment of neuropathy less favorably than adults and their response also depends on the pathomechanism of the ulnar nerve injury. A surgeon's or anesthetist's failure to recognize all of these specifics in children may result in substantial morbidity of young patients leading to lawsuits. Fortunately, with an adequate knowledge of surgical anatomy and types of procedures and positions in which the ulnar nerve is particularly vulnerable, and familiarity with measures to minimize the potential for neuropathy, this serious complication can be prevented. The aims of this review are to highlight personal experience and current knowledge of the rare position-related ulnar neuropathy, both from a clinical and anatomical-pathophysiological perspective, and to raise awareness about this rare but serious complication in the pediatric population.