Surgical Anatomy Research Articles

Female near-TME: standardization of proctectomy in women with ulcerative colitis

Traditionally, 2 surgical techniques for proctectomy in ulcerative colitis have been used: total mesorectal excision (TME), and close rectal dissection (CRD). Recently, our research group has proposed the standardization of the Near-TME technique, which unites the advantages of both methods. It decreases the risk of pelvic autonomic nerve injury and reduces the volume of mesorectal remnant. When performing the Near-TME, the anatomical landmarks differ between men and women, especially in the anterolateral hemicircumference. The objective of this paper is to standardize the Near-TME technique in women (Female Near-TME) using characteristic surgical-anatomic landmarks of the female pelvis based on illustrations and a real case treated laparoscopically.This technique should be carried out by surgeons with experience in inflammatory bowel disease surgery and extensive knowledge of surgical anatomy.

The surgical anatomy of the inferior alveolar nerve: a meta-analysis with clinical implications

The surgical anatomy of the inferior alveolar nerve: a meta-analysis with clinical implications

MRI of brachial plexus using diffusion tensor imaging: a pilot study for the use of resolve sequence surgical and radiologic anatomy.

Clinical exam is the goldstandard for surgical indication. ENMG and conventional MRI are insufficient to understand the highly variable clinical presentation of brachial plexus (BP) lesions. DTI is based on motion of water molecules and can explore nerve function. This pilot study of healthy subjects aimed to develop RESOLVE sequence for BP exploration using diffusion MRI. The main objective was to provide complete precise information from DTI cartography associated with anatomical data. Six healthy volunteers were scanned using 3T PRISMA scanner with anatomic 3D STIR SPACE and RESOLVE diffusion sequences. Diffusion parametric maps of fractional anisotropy (FA) were extracted from RESOLVE acquisitions. A reproducible method for roots volumes and angles measurements was created using 3DSlicer. ROI were segmented on Mean B0 sequences. FA measurements were obtained with ROI on Mean B0 sequences. RESOLVE sequence was adapted to the BP. Mean FA was 0.30. Angles measurements on 3D STIR SPACE sequences showed increasing values from proximal to distal roots with an 0.6 ICC. Volume measurements on anatomic sequences varied widely from one root to another but did not show any significant difference on laterality. A new and reproducible method for BP exploration was developed, using MRI RESOLVE DTI sequences. Complete mapping was obtained but a low resolution of track density imaging did not allow to exploit distal nerves. Deterministic tractography principal limit was the lack of resolution. Extraction of diffusion, volumetric and angular parameters of the plexus roots, and scripts creation for image processing was adapted to the healthy BP.

3D color multimodality fusion imaging as an augmented reality educational and surgical planning tool for extracerebral tumors.

Extracerebral tumors often occur on the surface of the brain or at the skull base. It is important to identify the peritumoral sulci, gyri, and nerve fibers. Preoperative visualization of three-dimensional (3D) multimodal fusion imaging (MFI) is crucial for surgery. However, the traditional 3D-MFI brain models are homochromatic and do not allow easy identification of anatomical functional areas. In this study, 33 patients with extracerebral tumors without peritumoral edema were retrospectively recruited. They underwent 3D T1-weighted MRI, diffusion tensor imaging (DTI), and CT angiography (CTA) sequence scans. 3DSlicer, Freesurfer, and BrainSuite were used to explore 3D-color-MFI and preoperative planning. To determine the effectiveness of 3D-color-MFI as an augmented reality (AR) teaching tool for neurosurgeons and as a patient education and communication tool, questionnaires were administered to 15 neurosurgery residents and all patients, respectively. For neurosurgical residents, 3D-color-MFI provided a better understanding of surgical anatomy and more efficient techniques for removing extracerebral tumors than traditional 3D-MFI (P < 0.001). For patients, the use of 3D-color MFI can significantly improve their understanding of the surgical approach and risks (P < 0.005). 3D-color-MFI is a promising AR tool for extracerebral tumors and is more useful for learning surgical anatomy, developing surgical strategies, and improving communication with patients.

Validation of a low-cost model for training laparoscopic ovary-sparing surgery (LOSS) in ovarian mature teratomas

BackgroundMature ovarian teratoma is the most common ovarian neoplasm in pediatrics. Laparoscopic ovary sparing surgery (LOSS) is effective and safe. Due to the expansion of this technique in recent years, education-based surgical simulation is a useful tool for skills development. AimTo validate a low-cost model for training LOSS in pediatric ovarian teratomas. MethodsWe developed a low-cost model, incorporated into Hands-On courses since 2018. After academic lectures, and surgical strategies video demonstration, all participants performed the procedure in pairs, in our pediatric gruyer-like-training-box, under supervision. Time and critical maneuvers were assessed. A Likert-type scale was used to evaluate: previous experience, anatomical appearance of the model, surgical anatomy compared to a real patient and utility as a training method. Statistical analysis was performed with R-Studio®. Results75 % considered the model as good or high degree of similarity in relation to the anatomical characteristics; and 91.3 % in relation to surgical anatomy. 78.8 % believe the model improves the majority of skills. Correlation in time assessment for 81 participants with different levels of experience was statistically significative (p<0.01*). Emphasis was placed on preserving the capsule and ovarian tissue without causing any injury to adjacent tissues, resulting in a homogeneous performance. ConclusionWe saw a correlation between the previous experience of the surgeon and their performance in the model. Introducing this model in a simulation curricula would improve the learning curve. A decrease in surgical technique complications is to be expected, and should be demonstrated in future studies.

Anteromedial Petrous (Gardner's) Triangle: Surgical Anatomy and Relevance for Endoscopic Endonasal Approach to the Petrous Apex and Petroclival Region.

Triangular corridors have been used as reliable surgical entry points for open transcranial approaches to the petrous apex (PA) and petroclival region (PCR). The endoscopic endonasal approaches have grown rapidly in the last decade, and the indications have advanced. The knowledge of accurate and reliable anatomic landmarks through endoscopic endonasal route is essential and remain to be established. The purpose of this study was to describe the feasibility and surgical exposure of the anteromedial petrous (Gardner's) triangle as a novel corridor to the PA and PCR. Five anatomic specimens were dissected. The PA and PCR were accessed through endoscopic endonasal approaches and contralateral transmaxillary approach. The limits of the anteromedial petrous (Gardner's) triangle were identified and dissected and associated measurements performed. The dissection was divided into 6 steps. The limits of the anteromedial petrous (Gardner's) triangle were identified and defined by the paraclival internal carotid artery anterolaterally, the abducens nerve posteromedially, and the petroclival synchondrosis inferiorly. Three lines were established following the limits of the triangle. The mean distance of the anterolateral limit was 10.03 mm (SD = 0.94), of the posteromedial limit was 20.06 mm (SD = 2.90), and of the inferior limit was 17.99 mm (SD = 2.99). The mean area was 87.56 mm 2 (SD = 20.06). The 3 anatomic landmarks with a critical role to safely define the triangle were the pterygosphenoidal fissure, the petrosal process of the sphenoid bone, and the petroclival synchondrosis. The anteromedial (Gardner's) triangle is a well-defined bone corridor which provides access to the entire petrous bone and petroclival junction through endoscopic endonasal route. Regardless of the anatomic variations or tumor location, the landmarks of the abducens nerve, paraclival internal carotid artery, and petroclival synchondrosis are key for understanding lateral access to tumors extending from the clivus.

Quadruple Arterial Blood Supply to the Liver: A Rare Variation

Introduction: Vascular variations in the liver are significant to surgeons in liver transplantations, radiological procedures, laparoscopy and penetrating abdominal injuries. These variations are important in liver transplantation procedure, in addition to being an ideal opportunity for surgical anatomy study, their detailed identification is crucial to the success of the procedure.&#x0D; Case Report: During a routine cadaveric dissection of the abdomen for medical students at the department of Anatomy Usmanu Danfodiyo University, Sokoto Nigeria. A male adult cadaver with unknown identity and cause of death, was found to have four arterial branches to the liver, one each from the left gastric artery and common hepatic artery, a branch from the gastro-duodenal artery and the hepatic artery.&#x0D; Conclusion: Detailed knowledge of the variations of hepatic arterial anatomy is of utmost importance to surgeons who perform surgeries in this area, particularly in liver transplantation, since their identification and proper management are critical to the success of the procedure.

Anatomical Step-by-Step Dissection of Complex Skull Base Approaches for Trainees: Surgical Anatomy of the Bifrontal Transbasal Approach, Surgical Principles, and Illustrative Cases

Abstract Introduction The transbasal approach traditionally uses a bicoronal scalp incision with bifrontal craniotomy to establish an extradural midline skull base working corridor. Depending on additional craniofacial osteotomies, this approach can expand its reach to the nasal cavity and paranasal sinuses and may be employed for the resection of particularly complex sinonasal and midline skull base tumors. Given its discrepancy in nomenclature and differences in interoperator technique, we propose a practical, operatively oriented guide for trainees performing this approach. Methods Three formalin-fixed, latex-injected specimens were dissected under microscopic magnification and endoscopic-assisted visualization. Stepwise dissections of the transcranial-transbasal approach with common modifications were performed, documented with three-dimensional photography, and supplemented with representative case applications. Results The traditional transbasal approach via bifrontal craniotomy affords wide extradural access to the anterior cranial fossa and central skull base. The addition of craniofacial osteotomies further expands access into the sinonasal cavities, clivus, and craniocervical junction. Key steps described include patient positioning, bicoronal skin incision, pericranial graft harvest, bifrontal craniotomy, orbital rim osteotomy, sphenoidotomy, bilateral ethmoidectomies, and microsurgical dissection of the sellar region. Basal superior sagittal sinus ligation and durotomy allow for intradural exposure. Reconstruction techniques are also discussed. Conclusion While the transbasal approach is rich with historical descriptions, illustrations, and modifications, its stepwise performance may be relatively unknown and unclear to younger generations of trainees. We present a comprehensive guide to optimize familiarity with the transbasal approach and its indications in the surgical anatomy laboratory, mastery of the relevant microsurgical anatomy, and simultaneous preparation for learning and participation in the operating room.

Anatomy-driven complexity classification for soft-tissue tunneling procedures.

The tunnel technique (TUN) preserves the integrity of the papilla by creating envelope flaps that allow for the insertion of a connective tissue graft, and/or biomaterials. (1) A comprehensive overview of tunneling flap procedures in the treatment of gingival recessions (GRs) for soft tissue coverage is presented and (2) A classification system for soft and hard tissue anatomy of GR sites which may aid the clinician in determining the surgical complexity is being introduced. A novel clinical classification system is proposed to illustrate complexity levels determined by soft and hard tissue anatomy of GR sites such as the mucogingival junction proximity to the gingival margin, bone morphotype, and mucosal margin thickness. TUN is highly effective in treating single/multiple GRs. Its limitations are related to variability in surgical site anatomy and operator expertise. A classification system based on anatomical soft and hard tissue variations has been proposed to help identify complexity levels encountered during tunneling procedures. Site-related factors directly impact the surgical variables related to tissue trauma, flap tension, soft tissue management, muscle pull, and wound stability during the healing of gingival recessions (GRs). The achievement of expedited and favorable wound healing is crucial to obtaining quantitative and qualitative success in the treatment of GR and the long-term stability of root coverage. A classification system based on anatomical soft and hard tissue variations has been proposed to facilitate tunneling procedures while respecting surgical principles.

Neurosurgical Education Using Cadaver-Free Brain Models and Augmented Reality: First Experiences from a Hands-On Simulation Course for Medical Students.

Background and Objectives: Neurosurgery has been underrepresented in the medical school curriculum. Advances in augmented reality and 3D printing have opened the way for early practical training through simulations. We assessed the usability of the UpSurgeOn simulation-based training model and report first experiences from a hands-on neurosurgery course for medical students. Materials and Methods: We organized a two-day microneurosurgery simulation course tailored to medical students. On day one, three neurosurgeons demonstrated anatomical explorations with the help of life-like physical simulators (BrainBox, UpSurgeOn). The surgical field was projected onto large high-definition screens by a robotic-assisted exoscope (RoboticScope, BHS Technologies). On day two, the students were equipped with microsurgical instruments to explore the surgical anatomy of the pterional, temporal and endoscopic retrosigmoid approaches. With the help of the RoboticScope, they simulated five clipping procedures using the Aneurysm BrainBox. All medical students filled out a digital Likert-scale-based questionnaire to evaluate their experiences. Results: Sixteen medical students participated in the course. No medical students had previous experience with UpSurgeOn. All participants agreed that the app helped develop anatomical orientation. They unanimously agreed that this model should be part of residency training. Fourteen out of sixteen students felt that the course solidified their decision to pursue neurosurgery. The same fourteen students rated their learning experience as totally positive, and the remaining two rated it as rather positive. Conclusions: The UpSurgeOn educational app and cadaver-free models were perceived as usable and effective tools for the hands-on neuroanatomy and neurosurgery teaching of medical students. Comparative studies may help measure the long-term benefits of UpSurgeOn-assisted teaching over conventional resources.

Preliminary Experience with 3-Dimensional Exoscope-Assisted Laryngoplasty.

Laryngoplasty requires the manipulation of the vocal folds, which are not visible during the operation. The widespread use of this technique is limited by the need for adequate knowledge of anatomy, the small surgical field, and the high level of skill required for the procedure. An exoscope has been developed to provide a stereoscopic view similar to that of a microscope while using the same compact endoscopic tool. This study aimed to determine whether the three-dimensional (3D) exoscopic surgical technique could be applied to laryngoplasty and explore its possibility to ultimately replace the current approach. This was a retrospective case series analysis, which included 28 patients with hoarseness who underwent surgery with (Exoscope; n = 12) or without (Macrosurgery; n = 16) a 3D exoscope between July 2018 and February 2021. The feasibility of performing all surgical steps with the 3D exoscope was evaluated. The Exoscope and Macrosurgery groups were compared for surgical time, vocal function outcomes, and complications. Questionnaires were completed by medical staff regarding the usefulness of medical education. No intraoperative or postoperative complications occurred in either procedure. The operative time was similar in both groups. The vocal function outcomes were also comparable between the groups. Questionnaires revealed that the exoscope was useful in terms of sharing information on surgical procedures and anatomy, as well as functioning as an educational tool. While this was a preliminary study, our results indicated that the exclusive use of the 3D exoscope was feasible for open approaches. 4 Laryngoscope, 134:1813-1819, 2024.

Dynamic surgical anatomy using 3D reconstruction technology in complex hepato-biliary surgery with vascular involvement. Results from an international multicentric survey

IntroductionThree-dimensional liver modeling can lead to substantial changes in choosing the type and extension of liver resection. This study aimed to explore whether 3D reconstruction helps to better understand the relationship between liver tumors and neighboring vascular structures compared to standard 2D CT scan images. MethodsContrast-enhanced CT scan images of 11 patients suffering from primary and secondary hepatic tumors were selected. Twenty-three experienced HBP surgeons participated to the survey. A standardized questionnaire outlining 16 different vascular structures (items) having a potential relationship with the tumor was provided. Intraoperative and histopathological findings were used as the reference standard. The proper hypothesis was that 3D accuracy is greater than 2D. As a secondary endpoint, inter-raters’ agreement was explored. ResultsThe mean difference between 3D and 2D, was 2.6 points (SE: 0.40; 95 % CI: 1.7–3.5; p < 0.0001). After sensitivity analysis, the results favored 3D visualization as well (mean difference 1.7 points; SE: 0.32; 95 % CI: 1.0–2.5; p = 0.0004). The inter-raters’ agreement was moderate for both methods (2D: W = 0.45; 3D: W = 0.44). Conclusion3D reconstruction may give a significant contribution to better understanding liver vascular anatomy and the precise relationship between the tumor and the neighboring structures.

Minimally invasive keyhole approach for supramaximal frontal glioma resections: technical note.

The authors aimed to review the frontal lobe's surgical anatomy, describe their keyhole frontal lobectomy technique, and analyze the surgical results. Patients with newly diagnosed frontal gliomas treated using a keyhole approach with supramaximal resection (SMR) from 2016 to 2022 were retrospectively reviewed. Surgeries were performed on patients asleep and awake. A human donor head was dissected to demonstrate the surgical anatomy. Kaplan-Meier curves were used for survival analysis. Of the 790 craniotomies performed during the study period, those in 47 patients met our inclusion criteria. The minimally invasive approach involved four steps: 1) debulking the frontal pole; 2) subpial dissection identifying the sphenoid ridge, olfactory nerve, and optic nerve; 3) medial dissection to expose the falx cerebri and interhemispheric structures; and 4) posterior dissection guided by motor mapping, avoiding crossing the inferior plane defined by the corpus callosum. A fifth step could be added for nondominant lesions by resecting the inferior frontal gyrus. Perioperative complications were recorded in 5 cases (10.6%). The average hospital length of stay was 3.3 days. High-grade gliomas had a median progression-free survival of 14.8 months and overall survival of 23.9 months. Keyhole approaches enabled successful SMR of frontal gliomas without added risks. Robust anatomical knowledge and meticulous surgical technique are paramount for obtaining successful resections.

Percutaneous Transhepatic Cholangioscopy Interventions-Updates.

Percutaneous transhepatic cholangioscopy (PTCS) was initially described around the same time that peroral cholangioscopy (POSC) was developed. The cited utility attributed to PTCS is the ability to be utilized in the subset of patients with surgical proximal bowel anatomy, often precluding the use of traditional POSC. However, since first described, PTCS use has been limited due to a lack of physician awareness and a lack of procedure-specific equipment and supplies. With recent developments of PTSC-specific equipment, there has been an expansion in the possible interventions able to be performed during PTCS, resulting in a rapid increase in clinical use. This short review will serve as a comprehensive update of the previous and more recent novel interventions now able to be performed during PTCS.

Anatomical Step-by-Step Dissection of Complex Skull Base Approaches for Trainees: Surgical Anatomy of the Endoscopic Endonasal Approach to the Anterior Cranial Fossa

Abstract Introduction The development of endoscopic techniques has made endoscopic endonasal approaches (EEAs) to the anterior cranial fossa (ACF) increasingly popular. Still, the steps and nuances involved in the approach may be difficult to understand for trainees. Thus, we aim to didactically describe the EEAs to the ACF in an anatomically based, step-by-step manner with supplementary clinical cases. Methods Six cadaveric head specimens were dissected. Endoscopic endonasal Draf I, IIA, IIB, and III frontal sinusotomies, endoscopic endonasal superior ethmoidectomy, and endoscopic endonasal transcribriform and transplanum approaches were modularly performed. The specimens were photodocumented with endoscopic techniques. Results Draf I frontal sinusotomy started with the complete removal of the anteromedial portion of the agger nasi cell, exposing the medial orbital wall, cranial base, and anterior cribriform plate. Draf II frontal sinusotomy proceeded with the removal of the floor of the frontal sinus between the lamina papyracea and the middle turbinate (IIa), and the nasal septum (IIb) until the first olfactory filaments were exposed. Draf III proceeded by creating a superior septal window just below the floor of the frontal sinus. The bone of the ACF bounded by the limbus sphenoidale posteriorly, frontal sinus anteriorly, and the medial orbital walls bilaterally was removed; the cribriform plate was removed; and the crista galli was dissected free from the dural leaflets of the falx cerebri and removed. Conclusion We provide a step-by-step dissection describing basic surgical steps and anatomy of the EEAs to the ACF to facilitate the learning process for skull base surgery trainees.

A Systematic Review of Varying Definitions and the Clinical Significance of Fredet's Fascia in the Era of Complete Mesocolic Excision.

Fredet's fascia represents a crucial landmark for vascular surgical anatomy, especially in minimally invasive complete mesocolic excision (CME) for right-sided colon adenocarcinoma. Fredet's fascia allows access to the gastrocolic trunk of Henle (GCTH), the most critical step in both open and minimally invasive right-sided CME techniques. Despite this, a recent workshop of expert surgeons on the standardization of the laparoscopic right hemicolectomy with CME did not recognize or include the term of Fredet's fascia or area. Hence, we undertook a systematic review of articles that include the terms "Fredet's fascia or area", or synonyms thereof, with special emphasis on the types of articles published, the nationality, and the relevance of this area to surgical treatments. We conducted a systematic review up to 15 July 2022 on PubMed, WOS, SCOPUS, and Google Scholar. The results of the study revealed that the term "Fredet's fascia" is poorly used in the English language medical literature. In addition, the study found controversial and conflicting data among authors regarding the definition of "Fredet's fascia" and its topographical limits. Knowledge of Fredet's fascia's surgical relevance is essential for colorectal surgeons to avoid accidental injuries to the superior mesenteric vascular pedicle during minimally invasive right hemicolectomies with CME. In order to avoid confusion and clarify this fascia for future use, we suggest moving beyond the use of the eponymous term by using a "descriptive term" instead, based on the fascia's anatomic structure. Fredet's fascia could, therefore, be more appropriately renamed "sub-mesocolic pre-duodenopancreatic fascia".

Surgical Anatomy of Transversus Abdominis Muscle for Transversus Abdominis Release: A CT-Based Study in Three Patient Groups.

The anatomy of the transversus abdominis muscle and its aponeurosis is important in transversus abdominis release surgery. We studied the CT anatomy of the transversus abdominis muscle medial to the linea semilunaris at different levels in the abdomen and measured the thickness of this muscle. In this retrospective study, we analysed 150 abdominal computed tomography at L1, L3, and L5 vertebral levels corresponding to subxiphoid, umbilical, and suprapubic regions, respectively. The patients were divided into three groups based on age and sex: women aged 15-20 years (nulliparous), women aged 30-60 years (multiparous), and men aged 15-60 years, with each group having 50 patients. We compared the thickness of the TA muscle at the L1 level between men and women and between nulliparous and multiparous women. Transversus abdominis muscle was consistently present medial to the linea semilunaris at L1 vertebral level in the subxiphoid region (150/150). At the L3 vertebral level in the mid-abdomen, only eight patients had the transversus abdominis muscle there (8/150, 5%). At the L5 vertebral level in the suprapubic region, no patient had the transversus abdominis muscle medial to the linea semilunaris. The mean thickness of the transversus abdominis muscle at the L1 level was 3.4 mm, and at the L3 level, it was 1.6 mm. There was no statistically significant difference in the transversus abdominis muscle thickness between the men and women; however, a significant difference was found between the nulliparous and multiparous women, with thinner TA muscle in later. There is good transversus abdominis muscle bulk medial to the linea semilunaris for doing transversus abdominis muscle division in the upper abdomen. However, as we move towards the mid-abdomen, we have TA aponeurosis or rarely TA muscle of little bulk.

Surgical Anatomy of the Ligamentous Attachments in the Superoposterior Scalp Region.

Hairline-lowering surgery has become increasingly popular in recent years, but little investigation into the surgical anatomy of the scalp has been performed. The aim of this study was to describe findings based on clinical observation and anatomic study of ligamentous attachments in the superoposterior region of the scalp. Six fresh cadaveric heads were dissected to identify connective tissue structures in the superoposterior scalp region. The areas of interest were along the sagittal suture towards the lambda, the obelion, and around the lambdoid suture. The location and dimensions of identified connective tissue attachments were documented with reference to described skeletal landmarks. Three distinct structures could be identified: (1) a cylindrical structure that sits at the posterior end of the sagittal suture with the parietal foramina in its base. This ligamentous structure extends from the pericranium into the galea, causes dimpling in the skin, and contains emissary veins. As this fulfills the criteria for an osseocutaneous retaining ligament, the term "cranial retaining ligament" is proposed. (2) Anterior to this ligament a connective tissue thickening was identified running along the sagittal suture and blending into the ligament, for which the term "sagittal adhesion" is proposed. (3) Another adhesion was identified just superior to the lambdoid suture, posterior to the retaining ligament, for which the term "supralambdoid adhesion" is proposed. Identification and better understanding of ligamentous structures in the superoposterior scalp allows for a safer and more effective advancement of the scalp in hairline-lowering surgery, which is a benefit to both patients and surgeons.

Surgical Anatomy of the Microscopic and Endoscopic Transorbital Approach to the Middle Fossa and Cavernous Sinus: Anatomo-Radiological Study with Clinical Applications.

The transorbital approaches (TOAs) have acquired growing notoriety, thanks to their ability to offer alternative corridors to the skull base. However, the limited access and the unfamiliarity with this surgical perspective make recognition of key landmarks difficult, especially for less experienced surgeons. The study wants to offer a detailed description of the anatomy to comprehend the potential and limitations of TOAs. Measurements of the orbit region and the surrounding areas were performed on two hundred high-resolution CT scans and thirty-nine dry skulls. Five specimens were dissected to illustrate the TOA, and one was used to perform the extradural clinoidectomy. Three clinical cases highlighted the surgical applications. A step-by-step description of the key steps of the TOA was proposed and a comparison with the transcranial anterior clinoidectomy was discussed. The mean work distance was 6.1 ± 0.4 cm, and the lateral working angle increased 20 ± 5.4° after removing the lateral orbital rim. TOAs are indicated in selected cases when tumor involves the lateral portion of the cavernous sinus or the middle skull base, obtaining a direct decompression of the optic nerve and avoiding excessive manipulation of the neurovascular structures. Comprehension of surgical anatomy of the orbit and its surrounding structures is essential to safely perform these approaches.

An Applied Anatomic Guide to Anterior Temporal Lobectomy and Amygdalohippocampectomy: Laboratory Cranial and White Matter Dissections to Inform Surgical Practice.

Anterior temporal lobectomy and amygdalohippocampectomy is a challenging procedure because of the deep surgical trajectory and complex regional neurovascular anatomy. A thorough knowledge of the involved anatomic structures is crucial for a safe and effective procedure. Our objective is to explore the white matter pathways in or around the operative corridor and to illuminate the 3-dimensional relationships of the pertinent operative parenchymal and skull base anatomy, aiming to inform and simplify surgical practice. Four normal, adult, cadaveric, formalin-fixed cerebral hemispheres (2 left and 2 right) treated with the Klinger's technique and 2 formalin-fixed and colored-latex-injected cadaveric heads (4 sides) were used. Focused white matter and cadaveric dissections were used to study the relevant anatomy implicated during an anterior temporal lobectomy. Four illustrative cases were also included. Digital photographs from every dissection step were obtained. Major white matter pathways that are inevitably traversed during the approach are the inferior longitudinal fasciculus, uncinate fasciculus, and inferior arm of the cingulum. Tracts that can be potentially injured, should the dissection plane tilt inadvertently superiorly or posteriorly, are the inferior fronto-occipital fasciculus, Meyer's loop, superior longitudinal fasciculus/arcuate fasciculus complex, and basal ganglia. Consistent cranial and parenchymal landmarks that can act as a roadmap during the procedure are recorded and paired with their intraoperative equivalent to provide a thorough, yet simple, stepwise guide for the surgeon. White matter dissections, cadaveric cranial dissections, and intraoperative images are put together to provide a simplified stepwise surgical manual for anterior temporal lobectomy. Laboratory investigations that focus on the intricate 3-dimensional relationships of the pertinent operative anatomy from the surgeon's eye may enrich anatomic knowledge and push surgical boundaries, to minimize complication rates and ultimately improve patient outcomes.