Functional Stimulation and Imaging to Predict Neuromodulation of Chronic Low Back Pain.

Back pain is one of the most common aversive sensations in human experience. Pain is not limited to the sensory transduction of tissue damage; rather, it encompasses a range of nervous system activities including lateral modulation, long-distance transmission, encoding, and decoding. Although spine surgery may address peripheral pain generators directly, aberrant signals along canonical aversive pathways and maladaptive influence of affective and cognitive states can result in persistent subjective pain refractory to classical surgical intervention. The clinical identification of who will benefit from surgery-and who will not-is increasingly grounded in neurophysiology.

Blood pressure cuff-induced radial nerve palsy following minimally invasive lateral microdiscectomy: illustrative case.

BACKGROUND: The authors describe a rare case of transient postoperative wrist and finger drop following a prone position minimally invasive surgery (MIS) lateral microdiscectomy. OBSERVATIONS: Hand and wrist drop is an unusual complication following spine surgery, especially in prone positioning. The authors' multidisciplinary team assessed a patient with this complication following MIS lateral microdiscectomy. The broad differential diagnosis included radial nerve palsy, C7 radiculopathy, stroke, and spinal cord injury. Given the patient's supinator weakness, intact pronation and wrist flexion, and transient recovery within 4 weeks, the most likely diagnosis was radial nerve neuropraxia secondary to ischemic compression. After careful consideration of the operative environment and anatomical constraints, the patient's blood pressure cuff was found to be the most probable source of compression. LESSONS: Blood pressure cuff-induced peripheral nerve injury may be a source of postoperative radial nerve neuropraxia in patients undergoing spine surgery. Careful considerations must be given to the blood pressure cuff location, which should not be placed at the distal end of the humerus due to higher susceptibility of peripheral nerve compression. Spine surgeons should be aware of and appropriately localize postoperative deficits along the neuroaxis, including central versus proximal or distal peripheral injuries, in order to guide appropriate postoperative management.

Hypertonic Saline Treatment in Traumatic Brain Injury: A Systematic Review.

Hypertonic saline (HTS) is a widely used adjunct in the treatment of traumatic brain injury (TBI). However, there is significant variability in practice patterns. Toward the goal of optimality and standardization in the use of HTS in TBI, we performed a comprehensive review of clinical protocols reported in the neurosurgical and neurocritical care literature. PubMed, Web of Science, Cochrane, Scopus, and Embase were independently queried between October and November 2021. The PRISMA guidelines were used throughout the screening process. We identified 15 high-quality studies representing data from 535 patients. We extracted patient demographics, Glasgow Coma Scale (GCS) score, mechanism of injury, HTS dosage, and rate of administration. Various HTS concentrations including 3%, 5%, 7.2%, 7.5%, and 20% were used. Modes of HTS administration included bolus (n = 125) and infusion (n = 376). Average length of stay was 22.4 days. Patient GCS score on initiation of HTS was depressed (average mean, 7.15; average median, 4.25 for studies reporting mean and median GCS, respectively). Excluding 2 studies with ambiguous doses, the mean HTS dosage was 2.7 × 102 mL across 8 studies and 2.5 mL/kg across 5 (with average post-HTS osmolality level of 304.6 mOsm/L reported in 3 studies). Infusions of 3% and 7.5% HTS are the most used concentrations given their efficacy in reducing intracranial pressure (ICP) and improving GCS score. In addition, lower HTS concentrations strongly correlated with greater ICP reduction. Therefore, lower concentrations of HTS may be practical therapeutic agents for patients with TBI given their efficacy in ICP reduction and safer complication profile compared with greater HTS concentrations. Evidence-based parametric use of HTS stands to improve patient outcomes by standardization of varied clinical practice.

Stereotactic Radiosurgery for Glomus Jugulare Tumors: Systematic Review and Meta-Analysis.

BACKGROUND: Glomus jugulare tumors (GJTs) are benign paragangliomas of the jugular foramen. Traditional management of these tumors involves surgical resection; however, considering the proximity of these tumors to important neurovasculature, stereotactic radiosurgery (SRS) may be an appropriate noninvasive treatment to consider. The aim of this meta-analysis was to evaluate SRS as a treatment option for GJTs. METHODS: An online search using PubMed, Web of Science, Scopus, and Cochrane databases was performed in March 2019 for articles on radiosurgery treatment of GJTs. The screening process followed Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. RESULTS: The final analysis comprised 23 studies including 460 patients. Average rates of tinnitus, hearing loss, and lower cranial nerve deficit as presenting symptoms were 56% (95% confidence interval [CI], 46%-66%), 56% (95% CI, 44%-68%), and 42% (95% CI, 31%-54%), respectively. Overall clinical status improvement rate after treatment was 47% (95% CI, 37%-57%). Rates of tinnitus, hearing loss, and lower cranial nerve improvement after treatment were 54% (95% CI, 44%-63%), 28% (95% CI, 19%-40%), and 22% (95% CI, 11%-39%), respectively. The mean follow-up time across studies was 47 months (range, 4-268 months). The aggregate tumor control rate at the time of follow-up was 95% (95% CI, 93%-97%). CONCLUSIONS: The tumor control rate of 95% and 47% symptomatic improvement suggest that SRS may be a suitable treatment modality for these hypervascular skull base tumors. Future studies are warranted to further evaluate the potential role of SRS in management of GJTs.

Clinical Efficacy of Frameless Stereotactic Radiosurgery in the Management of Spinal Metastases From Thyroid Carcinoma.

STUDY DESIGN: A retrospective data review. OBJECTIVE: To evaluate the efficacy of CyberKnife (CK) stereotactic radiosurgery (SRS) for thyroid spinal metastasis (SMs). SUMMARY OF BACKGROUND DATA: Thyroid carcinoma is an infrequent cause of SM. The absolute efficacy of SRS generally and CK in particular remains poorly characterized for thyroid SM. The current study is the first to specifically evaluate the efficacy of CK SRS for thyroid SMs. METHODS: A retrospective review of patients at our institution between 2003 and 2013 was done. Details about tumor location, radiographic findings before and after CK SRS, tumor recurrence, prescription isodose level, total and maximum dose, number of fractions, and gross tumor volume coverage were similarly collected. For comparison with other studies, the biologically effective dose and the equivalent total dose in 2 Gy fractions were calculated. Each patient was assessed for survival and local disease control from the time of the first CK session and survival analysis was carried out using the Kaplan-Meier method. Risk factors for local failure were assessed using multivariate logistic regression. RESULTS: A total of 12 patients with 32 spinal metastases from thyroid carcinoma that were treated with CK SRS were identified. Survival for 1, 2, and 3 years was 55%, 44%, and 33%, and local control was 67%, 56%, and 34% respectively. The study found that the single strongest factor associated with local control was prior radiotherapy (ß-coefficient -27.72, P = 0.01). No complications occurred in the immediate or late follow-up period. CONCLUSION: This was the first study to specifically investigate the efficacy of CK for treatment of thyroid SMs. Our findings suggest that CK can be safely used to treat spinal SMs from thyroid cancer and is associated with a high rate of local control. LEVEL OF EVIDENCE: 4.