Morris, Jonathan M.

Abstract BACKGROUND Glioma radiotherapy planning requires accurate tumor delineation. While T1- contrast-enhanced-MRI (T1-CE-MRI) is the standard, due to blood-brain-barrier breakdown dependencies, T1-CE-MRI fails to reflect the extent of glioma. Studies using amino acid PET tracers report glioma uptake up to 3cm-4cm beyond T1-CE. In this study, amino acid tracer 18F-fluoro-dihydroxyphenylalanine (18F-DOPA) uptake was correlated with histopathological features to determine tumor thresholds. METHODS Using registered 18F-DOPA-PET and T1-CE-MRI images in the Stealth Neuronavigation system targeting concordant and discordant regions, 181 stereotactic biopsy samples (newly-diagnosed=74; recurrent=107) were obtained from 59 enrolled astrocytoma patients across two prospective phase II clinical trials between 2010-2019. An experienced neuropathologist reviewed each sample with hematoxylin and eosin stain and assigned an alphanumeric score: mitotic activity (0=no tumor; 1=no mitosis; 2=few/scattered mitosis; 3=frequent mitosis) and cellular density (A=<25%; B=25%-50%; C=50%-75%; D=>75%). Samples assigned 1C-1D, 2B-2D, or 3A-3D were categorized as histopathological high-score (aggressive disease), remaining samples as low-score. Relative mean (rFDOPA_mean) tumor-to-background uptake ratios were computed for 5mm uniformly expanded volumes from each Stealth biopsy coordinate using the crescent and wedge normalization methods. Relative uptake was compared overall and separately within newly-diagnosed/recurrent disease subgroups. An optimal rFDOPA_mean threshold to delineate high- from low-score was determined using the maximal Youden index of ROC curves. RESULTS Overall, high-score samples (n=116) had higher median (IQR) rFDOPA_mean uptake than low-score samples (n=65): high-score rFDOPA:mean=1.70(1.16-2.26), low-score rFDOPA:mean=1.16(0.83-1.49), Kruskal-Wallis p<0.001. The uptake difference between high- vs. low-score samples was observed within newly-diagnosed and recurrent subgroups, but was only significant for newly-diagnosed (p<0.001). For newly-diagnosed, an rFDOPA:mean=1.49 cutoff between high- and low-score groups shows 69% accuracy, 63% sensitivity, 80% specificity (AUC=0.782). Using the wedge normalization method, rFDOPA_mean values were 0.2 higher than crescent method values. CONCLUSIONS This work presents histologically verified 18F-DOPA-PET thresholds for aggressive disease in newly-diagnosed astrocytoma patients. Separate thresholds will need to be determined for recurrent glioma patients.

Context.— Cardiac and pulmonary allograft recipients represent a unique population, frequently interacting with support groups and exhibiting intense curiosity about their pathology. Like other solid organ transplant patients, they have enduring and frequent interaction with the laboratory for routine allograft surveillance. Objective.— To address patient requests to understand what happens to their explanted organ and to better understand their disease while simultaneously improving awareness of pathologists’ roles in their continuing care. Design.— At routine follow-up appointments, transplant nurse coordinators offer each allograft recipient the opportunity to interact with a pathologist in our “ On My Path ” program. Organ viewing occurs in a private setting, in a specialized room. Relevant pathology is discussed, and questions are answered, with documentation in the medical record. The patient is subsequently gifted a 3-dimensional model of their explanted organ. Transplant coordinators were surveyed for their feedback on the experience. Results.— One hundred fifty-eight interactions have been documented (2017–2022) at our institution, including patients who underwent cardiac transplant (96, 61%), single or bilateral lung transplant (54, 34%), or combination lung and heart transplant (8, 5%). Transplant coordinators reported an increase in patient understanding of their disease and emotional closure related to the disease through the On My Path program. Conclusions.— Pathologists providing direct patient care is a feasible model that addresses currently unmet desires of the transplant population to better understand their pathology. Providing a 3-dimensional model helps to empower patients and drives satisfaction. These interactions also improve awareness about pathology as a discipline and its importance in the continued care of transplant recipients.

Study Design Survey study. Objectives The purpose of this study was to characterize the utility of 3D printed patient specific anatomic models for the planning of complex primary spine tumor surgeries. Methods A survey of individual members of an international study group of spinal oncology surgeons was performed. Participants were provided a clinical vignette, pathologic diagnosis, and pre-operative imaging for three primary spinal oncology cases. Study participants provided a free text surgical plan for resection and were then presented an associated 3D printed model for each case and asked to re-evaluate their surgical plan. Results Ten spinal oncology surgeons participated in the study, representing nine institutions across five countries. Four of the surgeons (40%) made significant changes to their surgical plan after reviewing the 3D models, including sacrifice of an additional nerve root to obtain negative margins, sparing an SI joint that was originally planned for inclusion in the en bloc resection, adjusting the location of osteotomy cuts, changes to the number of surgical stages and/or staging order, and preservation of neurology that was originally planned for sacrifice. The overall impression of the 3D models was positive, with 90% of the participants stating they found the 3D model useful in developing a surgical plan. Conclusions Surgical planning for resection of primary spinal column tumors is challenging and time intensive. 3D printed patient specific surgical models may be an additional tool that can augment surgical planning and execution by improving the chance of accomplishing surgical resection goals and minimizing morbidity.

Objectives The aim of this study was to create and validate a 3-dimensional (3D) ultrasound model with normal and abnormal pediatric hip joint anatomy that is comparable to a pediatric hip joint in appearance and anatomy and replicates sonographic characteristics of a pediatric hip joint. Methods A 3D rendering of the bone and soft tissue was created from a computed tomography pelvic scan of a pediatric patient. This rendering was modified to include a unilateral joint effusion. The bone was 3D printed with a photopolymer plastic, whereas the soft tissue was cast with a silicone mixture in a 3D-printed mold. The effusion was simulated by injecting saline into the soft tissue cavity surrounding the bone. The ultrasound model was validated by pediatric point-of-care ultrasonographers at an international pediatric ultrasound conference. Results A pediatric hip ultrasound model was developed that simulates both normal and abnormal pediatric hip joint anatomy, each with an appropriately sized, measurable joint effusion. Validation by pediatric point-of-care ultrasonographers showed that the key aspects of a normal pediatric hip joint (femoral physis, sloped femoral neck, and adequate soft tissue) with an identifiable and measurable effusion were included in the ultrasound model. Conclusions In this study, we successfully created a cost-effective, reusable, and reproducible 3D pediatric hip ultrasound model. The majority of pediatric point-of-care ultrasonographers who evaluated the model agreed that this model is comparable to a pediatric patient for the purpose of teaching ultrasound skills and joint space measurement.

Abstract Introduction Skull base neuroanatomy is traditionally learned through two-dimensional anatomical atlases, which while are of unquestionable value, lack the nuanced association of three-dimensional relationships between fundamental anatomical structures relevant to surgical approaches. Surgically focused step-by-step anatomical dissections can augment trainee learning of complex skull base techniques, particularly multistep and nuanced techniques such as translabyrinthine and transcochlear approaches. Methods Translabyrinthine and transcochlear approaches were performed on six sides of three formalin-fixed latex-injected specimens. The study objective was the completion and photo documentation of the steps involved in the approach in order to provide a comprehensive, intelligible, and anatomically oriented resource for multilevel trainees. Illustrative case examples were prepared to supplement approach dissections. Results The translabyrinthine and transcochlear approaches offer unique lateral windows through the temporal bone into the posterior fossa, providing excellent access to pathology at the petrous apex, internal auditory canal, Meckel's cave, and anterolateral brainstem. The transcochlear approach, which is an anterior extension of the translabyrinthine, particularly provides excellent exposure of the prepontine region and clivus. Important surgical considerations include patient position, temporal bone drilling and identification of critical landmarks, dural opening and identification of neurovascular structures, and reconstruction/closure techniques. Conclusion The translabyrinthine and transcochlear approaches are fundamental techniques for lateral skull base and posterior fossa pathologies. Both approaches are hearing-sacrificing but often require minimal to no cerebellar retraction and deliver unique visualization of prepontine neurovascular structures. This step-by-step approach guide provides a unique practical and high-yield surgically oriented learning resource for neurosurgery and otolaryngology trainees.

OBJECTIVE The objective of this study was to describe the quantitative features of intraoperative electromyographic recordings obtained from cranial nerve III, IV, and VI neuromonitoring using 25-mm intraorbital electrodes, in the larger context of demonstrating the practicality of this technique during neurosurgical cases. METHODS A 25-mm-long shaft-insulated intraorbital needle electrode is routinely used at the authors’ institution for extraocular muscle (EOM) electromyographic monitoring of the inferior rectus, superior oblique, and/or lateral rectus muscles when their function is at risk. Cases monitored between January 1, 2021, and December 31, 2022, were reviewed for patient demographics, tumor location and pathology, EOMs monitored, pre- and postoperative examination, and complications from electrode placement. Compound muscle action potentials on triggered electromyography, as well as neurotonic discharges on free-run electromyography, were described quantitatively. RESULTS There were 141 cases in 139 patients reviewed during the 24-month time span, with 278 EOMs monitored (inferior rectus/superior oblique/lateral rectus muscles 68/68/142). Triggered electromyography yielded biphasic or triphasic compound muscle action potentials from EOMs with a mean onset latency of 1.51 msec (range 0.94–3.22 msec), mean maximal peak-to-trough amplitude of 1073.93 μV (range 76.75–7796.29 μV), and high specificity for the channel in nearly all cases. Neurotonic discharges were recorded in 30 of the 278 EOMs (with all 3 muscles represented) and associated with a greater incidence of new or worsened ophthalmoparesis (OR 4.62, 95% CI 1.3–16.4). There were 2 cases of small periorbital ecchymosis attributed to needle placement; additionally, 1 case of needle-related intraorbital hematoma occurred after the review period. CONCLUSIONS The 25-mm shaft-insulated intraorbital electrode facilitates robust and consistent electromyographic recordings of EOMs that are advantageous over existing techniques. Combined with the relative ease of needle placement and low rate of complications, the technique is practical for neuromonitoring during craniotomies.