The Benefits of Progressive Occipital Condylectomy in Enhancing the Far Lateral Approach to the Foramen Magnum.

BACKGROUND: The portion of the occipital condyle that is safe to remove remains controversial in the transcondylar approach. We aimed to correlate the gain in exposure with incremental removal of the occipital condyle to determine if there is a point where further drilling yields diminishing gains. METHODS: Virtual reality rendering of the skull was generated from 25 subjects with no posterior fossa pathology. A suboccipital far lateral craniotomy was done in virtual reality space, stopping at the posterior edge of the occipital condyle. Angular measurements of surgical corridor were taken at this point and after removal of 25% and 50% of the condyle. Two surgical targets were used: at the anterior midline of the foramen magnum and the vertebrobasilar junction. RESULTS: Progressive removal of the occipital condyle increased exposure to both targets in a linear fashion. For the midline of the foramen magnum, the working angle increased from 12° to 18° for quarter condylectomy and then to 25° for half condylectomy. The corridor to the vertebrobasilar junction was much tighter, and the angle increased from 5.5° to 9° for quarter condylectomy and then to 12° for half condylectomy. The gain in exposure for the low target was greater than for the high target (P \u3c 0.001). CONCLUSIONS: Progressive removal of the occipital condyle yielded a linear increase in exposure without an ideal point beyond which the drilling was futile. However, the impact of condylectomy was greater for our low target compared with our high target

Progressive Orbitotomy and Graduated Expansion of the Supraorbital Keyhole: A Comparison with Alternative Minimally Invasive Approaches to the Paraclinoid Region.

BACKGROUND: Various minimally invasive approaches, such as supraorbital (SO), minipterional (MPT), and translateral orbital (TLO), can access the paraclinoid region. Studies have described these approaches individually but have not directly compared all of them in the same anatomic specimen. METHODS: Using virtual reality models generated from computed tomography studies of living subjects, we simulated TLO, MPT, and variations of SO approaches, without and with removal of the orbital rim and sphenoid wing. We measured the area of freedom (AOF), distance, and angle of attack to 4 paraclinoid targets: anterior clinoid process, optic foramen, lateral superior orbital fissure, and maxillary strut. RESULTS: For superiorly positioned targets, such as anterior clinoid process and optic foramen, MPT provided a larger AOF compared with the supraorbital approach. However, with progressive drilling of the orbital roof and lesser wing of the sphenoid, the SO corridor AOF was equivalent to MPT at the anterior clinoid process and larger at the optic foramen (P = 0.003). To the lateral superior orbital fissure, TLO had the most limited AOF, and MPT had the greatest (P \u3c 0.01 for all comparisons). For the maxillary strut, MPT, TLO, and SO with orbitotomy and sphenoidectomy all provided a similar AOF. CONCLUSIONS: For surgical targets in the paraclinoid region, MPT provided a greater AOF and shorter distance compared with TLO and limited SO approaches. With progressive enlargement of the SO corridor, SO with orbitotomy and sphenoidectomy matched and occasionally superseded the AOF of MPT. However, the AOF to inferomedial targets such as the maxillary strut was similar among all approaches

From CT to 3D Printed Models, Serious Gaming, and Virtual Reality: Framework for Educational 3D Visualization of Complex Anatomical Spaces From Within-the Pterygopalatine Fossa.

We describe the framework for capturing the internal view of complex anatomical spaces via multiple media and haptic platforms, exemplified by realistic and conceptual representations of the pterygopalatine fossa (PPF). A realistic three-dimensional (3D) mesh of the PPF was developed by segmenting the osseous anatomy on computed tomography (CT) using Materialize InPrint. Subsequently in Autodesk 3D Studio Max, the realistic mesh was enhanced with graphically designed neurovascular anatomy and additionally a conceptual representation of the PPF with its connections and contents was created. An interactive web-compatible Adobe Flash tutorial using ActionScript was developed, allowing users to advance through a series of educational slides that contained interactive rotatable interior camera views and scrollable CT cross-sectional content, incorporating both the realistic and conceptual models. Both models were also 3D printed using polyamide material. In the realistic model, the neurovasculature was colored with water-based acrylic paint. A 3-piece modular design with embedded magnets allows for internal visualization and seamless assembly. A serious gaming environment of the conceptual PPF was also developed using Truevision3D application programming interface, where users can freely move around rooms and hallways that represent various spaces. Lastly, the realistic model was incorporated into a headset-based virtual reality environment, Surgical Theater, allowing visualization and fly-through inside and outside the model. Multiple 3D techniques for visualization of complex 3D anatomical spaces from within were described, with the necessary software and skills detailed. A rough estimate of the time and cost needed to develop these tools as well as multiple supplementary source and end result files are also made available. Educators could utilize multiple advanced delivery methods to incorporate custom digital 3D models of complex anatomical spaces understood from inside

Common Iliac Artery to Below-Knee Popliteal Artery Bypass via Obturator Foramen in a Third-Time Reoperative Groin for Limb Salvage in Chronic Limb-Threatening Ischemia

This case report presents the management of a 69-year-old man with an extensive history of peripheral vascular disease including 2 previous failed right femoral to distal bypasses and a left above-the-knee amputation who presented with right lower extremity rest pain and non-healing shin ulcers. A redo bypass was performed for limb salvage via the obturator foramen to avoid his extensively scarred femoral region. The postoperative course was uneventful and the bypass remained patent in the early period. This case demonstrates the usefulness of the obturator bypass to provide revascularization and avoid amputation in a patient with chronic limb-threatening ischemia and multiple failed bypasses

Open versus minimally invasive small bowel resection for Crohn\u27s disease: a NSQIP retrospective review and analysis

INTRODUCTION: Many patients with Crohn\u27s Disease will require surgical resection. While many studies have described outcomes following ileocecectomy, few have evaluated surgical resection of other portions of small bowel. We sought to compare open and minimally invasive surgery (MIS) approaches for small bowel resection excluding ileocecectomy of patients with Crohn\u27s Disease using the National Surgical Quality Improvement Program (NSQIP) database. METHODS: The NSQIP database was queried for patients with Crohn\u27s disease or complications related to Crohn\u27s disease who underwent segmental small bowel resection utilizing open or minimally invasive approaches between 2012 and 2018. Patients requiring ileocecectomy or diagnosed with ascites, disseminated cancer, pre-operative sepsis, ASA class 5, and patients requiring mechanical ventilation were excluded. The association of pre-operative variables including patient demographic information and comorbidities with surgical approach were examined using Fishers exact test. Intraoperative, and 30-day post-operative outcomes were compared between the groups using both univariate and multivariate logistical regression models. SAS was used for data analysis with p \u3c 0.05 considered significant. RESULTS: After exclusions, we found 1697 patients with Crohn\u27s disease who underwent segmental small bowel resection, 1252 of whom underwent open surgery and 445 of whom underwent MIS. After adjusting for possible confounders with multivariable analysis, patients who underwent MIS had a lower incidence of wound events (surgical site, organ space, or deep wound infection, or dehiscence), post-operative bleeding, need for return to the operating room, and shorter total hospital length of stay despite longer operative times compared with open surgery. CONCLUSIONS: This retrospective review of NSQIP shows that minimally invasive small bowel resection is associated with equivalent or improved morbidity over open surgery in select patients with small bowel Crohn\u27s Disease. We show that in select patients minimally invasive small bowel resection can be safe and performed for patients with isolated small bowel Crohn\u27s disease

Disparities in utilization of robotic surgery for colon cancer: an evaluation of the U.S. National Cancer Database

Despite the benefits of minimally invasive surgery for colorectal procedures, significant disparities in access to these techniques remain. While these gaps have been well-documented for laparoscopy, few studies have evaluated inequalities in access to robotic surgery. We analyze whether disparities exist in the use of robotic surgery in the management of colon cancer. The U.S. National Cancer Database was queried for patients with non-metastatic colon adenocarcinoma who underwent resection with the robotic platform (2010-2016). Demographic, clinicopathologic, and treatment facility-related variables were analyzed with respect to preferential utilization of robotic surgery with multivariable logistic regression. Patients with metastatic disease, missing or incomplete surgical information, and those who underwent local tumor excision were excluded. 74,984 patients were identified, 3001 (4%) of whom underwent robotic surgery. In multivariable analysis, patients who were older, Black, or were living in an urban area had decreased odds of receiving robotic surgery compared with open or laparoscopic surgery. Patients who were privately insured or living in areas with higher education had increased odds of receiving robotic surgery. Robotic surgery was also preferentially associated with lower clinical stage, more recent year of diagnosis, and hospitals with higher procedural volume. As advantages of the robotic platform are becoming better understood, use of this approach is increasing in popularity for treatment of non-metastatic colon cancer. Despite this, significant disparities exist with respect to patient demographics and socioeconomic factors, and access may only be limited to certain types of hospitals. Further studies are needed to define why these inequalities exist

Study of comparative surgical exposure to the petroclival region using patient-specific, petroclival meningioma virtual reality models.

OBJECTIVE: Despite advancement of surgical techniques, the attachments of petroclival meningiomas near the central clival depression (CCD) remain difficult to visualize. With existing methods, the amount of tumor near the CCD that is inaccessible through various approaches cannot be compared. Tumors distort the brainstem, changing the size of the operative corridor for some but not all approaches; therefore, using cadavers with normal posterior fossae makes it impossible to compare different approaches to the tumor. The authors used virtual reality (VR) models created from the imaging data of patients to compare various surgical approaches that have otherwise been incomparable in previous studies. METHODS: CT and MRI data obtained in 15 patients with petroclival meningiomas were used to create anatomically accurate 3D VR models. For each model, various surgical approaches were performed, and the surgical freedom to 6 targets of the regions were measured. Furthermore, portions of the tumor that were visually blocked by the brainstem or bony structures were segmented and recorded as blinded volumes for comparison. RESULTS: The extended retrosigmoid approach generated excellent exposure of the petroclival region, but for most specimens, there was inaccessible tumor volume adjacent to the brainstem (mean 641.3 mm3, SE 161.8). In contrast, the brainstem sides of the tumors were well-visualized by all the transpetrosal approaches. The blinded volume of the tumor was largest for the retrolabyrinthine approach, and this was statistically significant compared with all other approaches (mean 2381.3 mm3, SE 185.4). CONCLUSIONS: The authors performed a novel laboratory study by using patient CT and MRI data to generate 3D virtual models to compare surgical approaches. Since it is impossible to perform various approaches in separate surgeries in patients for comparison, VR represents a viable alternative for such comparative investigations

An anatomical study of the foramen of Monro: implications in management of pineal tumors presenting with hydrocephalus.

BACKGROUND: For pineal tumors presenting with hydrocephalus, simultaneous endoscopic third ventriculostomy (ETV) and tumor biopsy is commonly used as the initial step in management. To analyze the restriction which the foramen of Monro poses to this procedure, one must start with a detailed description of the microsurgical anatomy of the foramen in living subjects. However, the orientation and shape of the foramen of Monro make this description difficult with conventional imaging techniques. METHOD: Virtual reality technology was applied on MRIs on living subject without hydrocephalus, as well as patients with hydrocephalus, to generate precise anatomical models with sub-millimeter accuracy. The morphometry of the foramen of Monro was studied in each group. In addition, displacement of the margins of the foramen was studied in detail for simultaneous ETV and pineal tumor biopsy through a single burr hole. RESULTS: In 30 normal subjects, the foramen of Monro had oval-shaped openings averaging 5.23 mm CONCLUSIONS: The foramen of Monro is an oval-shaped cylinder that changes in size and orientation in the hydrocephalic patient. If universally applied to all patients regardless of foramen and tumor size, ETV/biopsy can displace structures around the Foramen of Monro up to 1 cm, which can potentially lead to neurological damage. Careful pre-operative assessment is critical to determine if a single burr hole approach is safe