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1.         Stevens MN, Gallant JN, Feldman MJ, et al. Management of postradiation late hemorrhage following treatment for HPV-positive oropharyngeal squamous cell carcinoma. Head Neck 2022;44:10 79–85. Abstract available from: https://pubmed.ncbi.nlm.nih.gov/35150023/

Acute hemorrhage is an uncommon but potentially deadly complication for patients with head and neck cancer, especially in patients receiving RT. Previous reports have focused on hemorrhage following RT in all head and neck subsites without isolating HPV-positive malignancies. In this article, the authors focus specifically on patients with previously treated HPV-positive OPSCC given (1) the increasing prevalence and survival of this population and (2) the critical role RT plays in its treatment. They detail patient characteristics and cancer treatments leading to hemorrhagic events and include the acute interventions used in these life-threatening situations to better characterize this patient population.

A total of 12 patients with HPV-positive OPSCC were included. Six patients had base of tongue (BoT) tumors and 6 patients had tonsil tumors. The majority of patients were male (83%) with a mean age at diagnosis of 58 years. Fifty percent had advanced primary tumors (T3/T4). Median time from completion of chemoradiation to first hemorrhagic event was 186 days (range 66–1466 days). Seven patients (58%) required intervention to secure their airway. All patients were evaluated for endovascular intervention, 6 (50%) were embolized. Eight patients (67%) had a second hemorrhagic event; median time to second bleed was 22 days (range 3–90 days).

CTA was performed for 11 patients and demonstrated active extravasation in 1 patient, pseudoaneurysm (2), a combination of both extravasation and pseudoaneurysm (1), luminal irregularity (5), and no radiographic indication of vessel abnormality (2).

Seven of the 12 patients in the cohort ultimately required tracheostomy to secure their airway. In this study population, once the airway was established, attention was turned to control of hemorrhage with oropharyngeal packing with or without thrombotic agents, resuscitation with blood products, prompt evaluation with CT angiography, and admission for ongoing observation and management. Given that 3 of the 12 patients were found to have biopsy-proven persistent or recurrent disease, biopsy should be strongly considered in patients with history of HPV-positive OPSCC presenting with oropharyngeal hemorrhage.

3 tables, 2 figures with catheter angio

2.         Karandikar P, Massaad E, Hadzipasic M, et al. Machine learning applications of surgical imaging for the diagnosis and treatment of spine disorders: Current state of the art. Neurosurgery 2022;90:37 2–82. Abstract available from: https://pubmed.ncbi.nlm.nih.gov/35107085/

Recent developments in machine learning (ML) methods demonstrate unparalleled potential for application in the spine. The ability for ML to provide diagnostic faculty, produce novel insights from existing capabilities, and augment or accelerate elements of surgical planning and decision making at levels equivalent or superior to humans will tremendously benefit spine surgeons and patients alike. In this review, the authors aim to provide a clinically relevant outline of ML-based technology in the contexts of spinal deformity, degeneration, and trauma, as well as an overview of commercial-level and precommercial-level surgical assist systems and decision support tools. They briefly discuss potential applications of generative networks.

While discriminative networks represent the bulk of ongoing efforts in medical ML, generative adversarial networks (GANs) are not yet a decade old at the time of writing yet represent a vast and as yet unexplored space for clinical applications. By definition, a generative adversarial network pits generator and discriminator networks against each other, ultimately producing objects that sufficiently imitate the training data to fool the discriminator network. As such, these systems can be tuned to focus on their generative or discriminative functions. While the latter (discriminator) largely resemble applications of NNs, the former (generative) can provide more efficient and/or accurate solutions to challenges in the methodology of imagery acquisition and analysis. GANs trained on radiographic imagery have been applied in the context of radiotherapy treatment plan generation, prediction of brain tumor growth patterns, and acceleration of image recompilation in an existing picture archiving and communication system. However, the greatest strength may lie in the “quality-of-life” improvements that GANs represent.

GAN-based imagery protocols have captured MR and CT images with reduced scan times, radiation doses, and contrast required. Retrospective GANs can intelligently denoise low quality imagery and correct for motion artifacts. A fascinating application of GAN involves intermodality conversion of imaging—MRI to CT, CT to MRI, and CT to cbCT. This functionality may enable the surgeon and the physician to benefit from the diagnostic insight of either modality while reducing costs to the patient or minimizing radiation dose. As such, although GAN methods are still in their infancy, successful implementation will dramatically improve the medical imagery workflow.

4 figures, 1 table

3.         Ren J, Jiang N, Bian L, et al. Natural history of spinal cord cavernous malformations: A multicenter cohort study. Neurosurgery 2022;90:39 0–98. Abstract available from: https://pubmed.ncbi.nlm.nih.gov/35049523/

Compared with their intracranial counterparts, spinal cord CMs (SCCMs) are more aggressive because of greater vulnerability of the tightly compacted eloquent cord structures within the narrow confine of the spinal canal. However, relatively little data exist on the natural history of SCCMs because of their rarity. Previous studies have suggested that the annual hemorrhagic rates of SCCMs ranged from 1.4% to 6.8%. All patients between 2002 and 2019 with diagnosis of SCCMs were identified retrospectively. An observational study of patients with conservative management was performed to reveal the natural history of SCCMs. The authors identified 305 patients in the full cohort, including 126 patients who were conservatively treated for at least 6 months (median observational period, 24.0 months). Forty-five hemorrhage events occurred during 527 person-years of follow-up, yielding an annual hemorrhage rate of 8.5% per person-year. The 1-, 2-, and 5-year cumulative risks of hemorrhage were 13.9%, 26.1%, and 35.1%, respectively. Prior hemorrhage and pediatric patients were independent predictors of hemorrhage in the long-term follow-up. Familial form and subsequent hemorrhage events were independent risk factors for worsening of neurologic function, and baseline neurologic status and presence of subsequent hemorrhage were significantly associated with neurologic outcomes.

The natural history of SCCMs is poor, variable, but predictable. Patients with SCCMs can be stratified to predict the future hemorrhage risks and neurologic impairment. Initial baseline characteristics significantly affect the natural history of the SCCMs, which prompts a differentiated treatment strategy.

2 figures, 5 tables, with MR images

4.         Beucler N, Dagain A. Historical vignette portraying the difference between the “sinking skin flap syndrome” and the “syndrome of the trephined” in decompressive craniectomy. World Neurosurg [Internet]. 2022;162:11 –14. Available from: https://doi.org/10.1016/j.wneu.2022.03.027

Decompressive craniectomy has been adopted as a possible therapeutic option for extreme cases of traumatic brain injury and malignant ischemic stroke. The history of decompressive craniectomy, though, involves civilian and military discoveries that have been progressively confused and even forgotten according to the authors. The syndrome of the trephined was introduced in 1939 as a feeling of tenderness, discomfort, and insecurity located at the site of craniectomy. Forty years later, in 1977, the sinking skin flap syndrome was defined as new-onset neurologic deficits or even coma associated with marked skin depression at the site of craniectomy, indicating urgent need for cranioplasty. These 2 syndromes illustrate the paradigm shift of the indications for cranioplasty, which have evolved from cosmetic reasons in the 1940s to cerebral metabolism improvement in the early 21st century.

The authors would like to raise the neurosurgical community’s awareness regarding SSFS, which is a rare, poorly known, and incompletely understood yet serious complication that can occur if cranioplasty if performed in a delayed fashion. SSFS is a neurosurgical emergency, the treatment of which involves Trendelenburg positioning until urgent cranioplasty can be performed. In contrast, the so-called ST can be described as the association of pain, discomfort, and a feeling of insecurity at the site of craniectomy, and should be clearly distinguished from SSFS.

1 table

5.         Abecassis IJ, Meyer RM, Levitt MR, et al. Recurrence after cure in cranial dural arteriovenous fistulas