Meges of Sidon: The "Most Learned" of Surgery's Founding Fathers.

This paper aims to bring back to life an underrated, even forgotten surgeon of the late first century B.C.E., Meges of Sidon. He was an experienced surgeon of his time and was considered the most erudite Roman surgeon before Galen. He belonged to the Alexandria School of Medicine and later migrated to Rome to practice. Although most of his work did not survive, he was mentioned by notable ancient figures, such as Celsus and Galen. He excelled in various surgical specialties, not limited to neurosurgery, orthopedics, ophthalmology, and urology. Galen cited Meges in his surgical book on head injuries and cranial procedures. Meges was known to have invented a "double-edged" blade that he used to remove stones from the neck of the bladder. His treatment of anal fistulas was a reference through the Middle Ages. Celsus, a Roman encyclopedist of the first century, would later erroneously receive credit for ancient surgical innovations, such as the nonslipping cranial drill and the treatment of depressed skull fractures, even though he was not a surgeon. However, as Celsus was going over the history of surgery, he described Meges as the "most learned" of its prominent figures. Meges' neurosurgic techniques and teachings are deduced from Celsus, who shortly succeeded him, did not practice surgery, and acknowledged him as his primary source on surgical topics.

Cisternal, Falciform, and Optic Canal Decompression Influencing Optic Nerve Biomechanics: A Microsurgical Anatomic Study.

BACKGROUND: Questions remain regarding optic nerve (ON) physiology, mechanical compliance, and microvasculature, particularly surgical outcomes and atypical visual field defects associated with sellar/parasellar pathology (eg, tumors and aneurysms). OBJECTIVE: To study the microsurgical/histological anatomy of each ON segment and corresponding microvasculature, calculate area of optic-carotid space at each decompression stage, and measure ON tension before/after compression. METHODS: Five cadaveric heads (10 sides) underwent sequential dissection: (1) intradural (arachnoidal) ON dissection; (2) falciform ligament opening; (3) anterior clinoidectomy, optic canal decompression, and ON sheath release. At each step, we pulled the nerve superiorly/laterally with a force meter and measured maximal mobility/mechanical tension in each position. RESULTS: Cisternal ON microvasculature was more superficial and less dense vs the orbital segment. ON tension was significantly lower with higher mobility when manipulated superiorly vs lateromedially. Optic-carotid space significantly increased in size at each decompression stage and with ON mobilization both superiorly and laterally, but the increase was statistically significant in favor of upward mobilization. At decompression step, upward pull provided more space with less tension vs side pull. For upward pull, each step of decompression provided added space as did side pull. CONCLUSION: Opening the optic canal, falciform ligament, and arachnoid membrane decompresses the ON for safer manipulation and provided a wider optic-carotid surgical corridor to access sellar/parasellar pathology. When tailoring decompression, the ON should be manipulated superiorly rather than lateromedially, which may guide surgical technique, help prevent intraoperative visual deterioration, facilitate postoperative visual improvement, and help understand preoperative visual field deficits based on mechanical factors.

History, Variations, and Extensions of the Retrosigmoid Approach: Anatomical and Literature Review.

The retrosigmoid approach is the workhorse for posterior fossa surgery. It gives a versatile corridor to tackle different types of lesions in and around the cerebellopontine angle. The term "extended" has been used interchangeably in the literature, sometimes creating confusion. Our aim was to present a thorough analysis of the approach, its history, and its potential extensions. Releasing cerebrospinal fluid from the subarachnoid spaces and meticulous microsurgical techniques allowed for the emergence of the retrosigmoid approach as a unilateral variation of the traditional suboccipital approach. Anatomical landmarks are helpful in localizing the venous sinuses and planning the craniotomy, and Rhoton's rule of three is the key to unlock difficult neurovascular relationships. Extensions of the approach include, among others, the transmastoid, supracerebellar, far-lateral, jugular foramen, and perimeatal approaches. The retrosigmoid approach applies to a broad range of pathologies and, with its extensions, can provide adequate exposure, obviating the need for extensive and complicated approaches.

The Asterion-to-Transverse Process of the Atlas Line as a Surgical Landmark.

Introduction Proposed landmarks to predict the anatomical location and trajectory of the sigmoid sinus have varying degrees of reliability. Even with neuronavigation technology, landmarks are crucial in planning and performing complex approaches to the posterolateral skull base. By combining two major dependable structures-the asterion (A) and transverse process of the atlas (TPC1)-we investigate the A-TPC1 line in relation to the sigmoid sinus and in partitioning surgical approaches to the region. Methods We dissected six cadaveric heads (12 sides) to expose the posterolateral skull base, including the mastoid and suboccipital bone, TPC1 and suboccipital triangle, distal jugular vein and internal carotid artery, and lower cranial nerves in the distal cervical region. We inspected the A-TPC1 line before and after drilling the mastoid and occipital bones and studied the relationship of the sigmoid sinus trajectory and major muscular elements related to the line. We retrospectively reviewed 31 head and neck computed tomography (CT) angiograms (62 total sides), excluding posterior fossa or cervical pathologies. Bone and vessels were reconstructed using three-dimensional segmentation software. We measured the distance between the A-TPC1 line and sigmoid sinus at different levels: posterior digastric point (DP), and maximal distances above and below the digastric notch. Results A-TPC1 length averaged 65 mm and was posterior to the sigmoid sinus in all cadaver specimens, coming closest at the level of the DP. Using the transverse-asterion line as a rostrocaudal division and skull base as a horizontal plane, we divided the major surgical approaches into four quadrants: distal cervical/extreme lateral and jugular foramen (anteroinferior), presigmoid/petrosal (anterosuperior), retrosigmoid/suboccipital (posterosuperior), and far lateral/foramen magnum regions (posteroinferior). Radiographically, the A-TPC1 line was also posterior to the sigmoid sinus in all sides and came closest to the sinus at the level of DP (mean, 7 mm posterior; range, 0-18.7 mm). The maximal distance above the DP had a mean of 10.1 mm (range, 3.6-19.5 mm) and below the DP 5.2 mm (range, 0-20.7 mm). Conclusion The A-TPC1 line is a helpful landmark reliably found posterior to the sigmoid sinus in cadaveric specimens and radiographic CT scans. It can corroborate the accuracy of neuronavigation, assist in minimizing the risk of sigmoid sinus injury, and is a useful tool in planning surgical approaches to the posterolateral skull base, both preoperatively and intraoperatively.

First documented clinical account of brachial plexus palsy from the 12th century.

OBJECTIVE: Although literary depiction of brachial plexus injury can be traced to Homer's Iliad, there is a scientific consensus that the first clinical description of brachial plexus palsy was not documented until the British physician Smellie reported it in the 18th century. However, the authors' recent review of the Syriac Book of Medicines (12th century) has uncovered a much earlier clinical documentation. METHODS: For this historical vignette, the authors reviewed the historical and anatomical literature regarding earlier descriptions of brachial plexus anatomy and pathology, including a thorough analysis of the Syriac Book of Medicines (attributed to an unknown Syriac physician in the Middle Ages) and Galen's On Anatomical Procedures and On the Usefulness of the Parts of the Body. RESULTS: Building on the galenic tradition with reference to independent dissections, the Syriac physician discussed nervous system anatomy and the clinical localization of neurological injuries. He described a patient who, after initial pulmonary symptoms, developed upper-extremity weakness more pronounced in the proximal muscles. His anatomical correlation placed the injury "where the nerves issue from the first and second muscles between the ribs" (scalene muscles), are "mixed," and "spread through many parts." The patient's presentation and recovery raise the possibility of Parsonage-Turner syndrome. The anatomical description of the brachial plexus is in line with Galen's earlier account and step-by-step surgical exposure, which the authors reviewed. They also examined Ibn Ilyas' drawing of the brachial plexus, which is believed to be a copy of the earliest artistic representation of the plexus. CONCLUSIONS: Whereas the Middle Ages were seen as a period of scientific stagnation from a Western perspective, Galen's teachings continued to thrive and develop in the East. Syriac physicians were professional translators, clinicians, and anatomists. There is evidence that brachial plexus palsy was documented in the Syriac Book of Medicines 6 centuries before Smellie.

Transcavernous Approach in Vascular Neurosurgery.

The cavernous sinus is no more considered no man's land. It is a very well organized anatomic entity that can safely be navigated. It is both a route and a destination. Unlocking the cavernous sinus provides a highway that can be used to reach different vascular and tumor locations that were deemed very risky to handle.

Simplifying the Surgical Classification and Approach to the Posterolateral Skull Base and Jugular Foramen Using Anatomical Triangles.

Introduction Lesions of the jugular foramen (JF) and postero-lateral skull base are difficult to expose and exhibit complex neurovascular relationships. Given their rarity and the increasing use of radiosurgery, neurosurgeons are becoming less experienced with their surgical management. Anatomical factors are crucial in designing the approach to achieve a maximal safe resection. Methods and methods Six cadaveric heads (12 sides) were dissected via combined post-auricular infralabyrinthine and distal transcervical approach with additional anterior transstyloid and posterior far lateral exposures. Contiguous surgical triangles were measured, and contents were analyzed. Thirty-one patients (32 lesions) were treated surgically between 2000 and 2016 through different variations of the retro-auricular distal cervical transtemporal approaches. Results We anatomically reviewed the carotid, stylodigastric, jugular, condylar, suboccipital, deep condylar, mastoid, suprajugular, suprahypoglossal (infrajugular), and infrahypoglossal triangles. Tumors included glomus jugulare, lower cranial nerve schwannomas or neurofibromas, meningiomas, chondrosarcoma, adenocystic carcinoma, plasmacytoma of the occipitocervical joint, and a sarcoid lesion. We classified tumors into extracranial, intradural, intraosseous, and dumbbell-shaped, and analyzed the approach selection for each. Conclusion Jugular foramen and posterolateral skull base lesions can be safely resected through a retro-auricular distal cervical lateral skull base approach, which is customizable to anatomical location and tumor extension by tailoring the involved osteo-muscular triangles.

Legacy of Syriac-Aramaic Scholars in Transmitting Neurosurgical Knowledge Between Antiquity and the Middle Ages.

The link between ancient Greek medicine and the Arabic translation period in the 9th century cannot be understood without studying the contributions of Syriac scholars. With their mastery of Greek and the related Semitic languages of Syriac and Arabic, they initiated a scientific translation process with methods that prevail to this day. In this paper, we reviewed Hunayn Ibn Isshaq's Ten Treatises on the Eye to elucidate the original contributions of the Syriac physicians to the field of neurologic surgery. We analyzed the oldest known diagram of orbital anatomy along with Hunayn's genuine ideas on the optic nerve anatomy and pathology, optic chiasm, afferent pupillary reflex, and papilledema and venous congestion. We also reviewed the neurosurgical elements found in the Syriac Book of Medicines including the thought process in localizing neurologic deficits based on clinical experience and anatomic dissections and the earliest recorded description of brachial plexus pathology.

Far Lateral Approach for Resection of Transverse Ligament Cyst.

Objectives This study was aimed to describe a far lateral approach for microsurgical resection of a transverse ligament cyst, with emphasis on the microsurgical anatomy and technique. Design A far lateral craniotomy is performed in the lateral decubitus position. After opening the dura laterally, dural sutures are placed for retraction. A stitch placed through the dentate ligament is advantageous to rotate the spinal cord to allow access to the ventral cyst. The cyst is marsupirlized and mass effect on the spinal cord is relieved. Photographs of the region are borrowed from Dr Rhoton's laboratory to illustrate the microsurgical anatomy. Participants The first author performed the surgery and edited the video. Chart review and literature review were performed by the other authors. Outcome Measures Outcome was assessed with postoperative neurological function. Results The patient was discharged home after an uneventful hospital course. At short-term follow-up, the patient had a significant improvement in postoperative strength. Conclusion The far lateral approach provides an adequate corridor to the ventrolateral brainstem in combination with utilization of the dentate ligament to reach ventral cysts compressing the spinal cord. An adequate understanding of the relevant microsurgical anatomy is a key to safe surgery in this region. The link to the video can be found at: https://youtu.be/5MGVPO2Q2pI .

Resection of a Recurrent Cervicomedullary Junction Fibromyxoid Sarcoma through a Far Lateral Approach.

Objectives This study describes a far lateral approach for the resection of a recurrent fibromyxoid sarcoma involving the ventrolateral brainstem, with emphasis on the microsurgical anatomy and technique. Design A far lateral craniotomy is performed in the lateral decubitus position and the transverse and sigmoid sinuses exposed. After opening the dura, sutures are placed to allow gentle mobilization of the sinuses. The recurrent tumor is immediately visible. The involved dura is resected and aggressive internal debulking is performed. Subarachnoid dissection gives access to the lower cranial nerves. The tumor is dissected off the affected portions of the brainstem. A dural graft is used to reconstitute the dura. Photographs of the region are borrowed from Dr. Rhoton's laboratory to illustrate the microsurgical anatomy. Participants The senior author performed the surgery. The video was edited by Dr. V.N. chart review, and literature review were performed by Drs. W.M. and J.B. Outcome measures Outcome was assessed with the extent of resection and postoperative neurological function. Results A near gross total resection of the lesion was achieved. The patient developed a left vocal cord paresis, but her voice was improving at 3-month follow-up. Conclusion Understanding the microsurgical anatomy of the craniocervical junction and ventrolateral brainstem and meticulous microneurosurgical technique are necessary to achieve adequate resection of lesions involving the ventrolateral brainstem. The far lateral approach provides an adequate corridor to this region. The link to the video can be found at: https://youtube/uYEhgPbgrTs .

Robotic-Assisted Tubular Transoral Parapharyngeal Approach to the Ventral Craniovertebral Junction.

BACKGROUND: Transoral robotic surgery (TORS) has become a routine technique for treating benign and malignant lesions of the oropharynx with the advantage of reducing morbidity compared to open surgical techniques. However, TORS has not been used routinely for accessing lesions of the spine. OBJECTIVE: To describe how TORS can be used to access spinal lesions. METHODS: We describe our technique of accessing the parapharyngeal space using the robotic technique, and then dissecting the prevertebral muscles to expose the ventral craniovertebral junction. Tubular retraction with endoscopic visualization is then employed for surgical resection. We then report a case of a 14-yr-old competitive athlete who presented with an osseous lesion of C1, which underwent resection using this novel TORS approach. RESULTS: Our patient underwent successful resection of a lateral C1 osteoid osteoma utilizing a combined TORS/endoscopic approach. She tolerated soft diet immediately and was discharged on postoperative day 2. Postoperative imaging revealed complete resection of the lesion, and she returned to competitive athletics within 6 wk. CONCLUSION: Utilizing this novel, robotic-assisted approach can definitively treat osseous cervical spine lesions while reducing morbidity, allowing for early return to normal diet and minimizing overall length of hospital stay.

Anterior perforated substance region aneurysms: review of a series treated with microsurgical technique.

Aneurysms arising from the distal carotid, proximal A1, and proximal M1 that project posteriorly and superiorly toward the anterior perforated substance (APS) are rare. Their open surgical treatment is particularly difficult due to poorly visualized origin of the aneurysm and the abundance of surrounding perforators. We sought to analyze the anatomical and clinical characteristics of APS aneurysms and discuss surgical nuances that can optimize visualization, complete neck clip obliteration, and preservation of adjacent perforators. Thirty-two patients with 36 APS aneurysms were surgically treated between November 2000 and September 2017. Patients were prospectively enrolled in a cerebral aneurysm database and their clinical, imaging, and surgical records were retrospectively reviewed. Twenty-seven aneurysms originated from the distal ICA, 7 from the proximal A1, and 2 from the proximal M1; 15 patients presented with subarachnoid hemorrhage. Careful intraoperative dissection revealed 4 aneurysms originating at the takeoff of a perforator; another 25 had at least 1 adherent perforator. All aneurysms were clipped except for one that was trapped. Postoperatively, 3 patients had radiographic infarctions in perforator territory with only 1 developing delayed clinical hemiparesis. Good outcome (modified Rankin Scale, 0-2) was achieved in 28 patients (88%). APS aneurysms present a challenging subset of aneurysms due to their complex anatomical relationship with surrounding perforators. These should be identified on preoperative imaging based on location and projection. Successful microsurgical clipping relies on optimization of the surgical view, meticulous clip reconstruction, preservation of all perforators, and electrophysiological monitoring to minimize ischemic complication.

Temporary Clipping of the Intracavernous Internal Carotid Artery: A Novel Technique for Proximal Control.

BACKGROUND: Securing proximal control in complex paraclinoid aneurysm surgery through traditional techniques may be challenging and risky in certain situations. Advancements of anatomical knowledge of the cavernous sinus (CS) and hemostasis have made it more accessible as a surgical option. OBJECTIVE: To describe the technique of temporary clipping of the horizontal segment of the intracavernous internal carotid artery (IC-ICA) in preparation for permanent clipping of complex paraclinoid aneurysms. METHODS: Through an extradural pretemporal approach, the lateral wall of the CS is exposed. The dura between the trochlear nerve and V1 is opened, and access is made to the horizontal segment of the IC-ICA. After circumferential dissection, the temporary clip can be introduced to the artery, and the extradural clinoidectomy can be continued under secured proximal control. RESULTS: Seven patients with complex paraclinoid aneurysms were treated between May 2013 and May 2016 by the senior author. Temporary clipping of the IC-ICA was performed in all cases. Average time to achieve proximal control was 22.6 min (22.6 ± 13.8). One patient developed transient oculomotor palsy postoperatively. There were no other complications. CONCLUSION: When the exposed clinoidal segment of the internal carotid artery does not offer sufficient proximal space for temporary clipping, the extradural approach can be extended to the horizontal portion of the IC-ICA. In our experience, this technique is a quick, reliable, and safe alternative to the classical modalities of temporary occlusion.

Morphometric Comparison of the Pterional Trans-Sylvian and the Pretemporal Trans-Clinoidal Approaches to the Posterior Communicating Artery.

BACKGROUND: Posterior communicating (Pcom) aneurysms in the modern era have tended toward increased complexity and technical difficulties. The pretemporal approach is a valuable extension to the pterional approach for basilar apex aneurysms, but its advantages for Pcom aneurysms have not been previously elucidated. OBJECTIVE: To quantify characteristics of the pretemporal approach to the Pcom. METHODS: We dissected 6 cadaveric heads (12 sides) with a pretemporal transclinoidal approach and measured the following variables: (1) exposed length of internal carotid artery (ICA) proximal to the Pcom artery; (2) exposed circumference of ICA at the origin of Pcom; (3) deep working area between the optic nerve and tentorium/oculomotor nerve; (4) superficial working area; (5) exposure depth; and (6) the frontotemporal (superior posterolateral) and (7) orbito-sphenoidal (inferior anterolateral) angles of exposure. RESULTS: Compared with pterional craniotomy, the pretemporal transclinoidal approach increased the exposed length of the proximal ICA from 3.3 to 11.7 mm (P = .0001) and its circumference from 5.1 to 7.8 mm (P = .0003), allowing a 210° view of the ICA (vs 137.9°). The deep and superficial working areas also significantly widened from 53.7 to 92.4 mm2 (P = .0048) and 252.8 to 418.2 mm2 (P = .0001), respectively; the depth of the exposure was equivalent. The frontotemporal and spheno-Sylvian angles increased by 17° (P = .0006) and 10° (P = .0037), respectively. CONCLUSION: The pretemporal approach can be useful for complex Pcom aneurysms by providing easier proximal control, wider working space, improved aneurysm visualization, and more versatile clipping angles. Enhanced exposure results in a potentially higher rate of complete aneurysm obliteration and complication avoidance.

Predicting Surgical Intervention in Cerebellar Stroke: A Quantitative Retrospective Analysis.

BACKGROUND: Debate still exists regarding whether preventive surgical decompression should be offered to high-risk patients experiencing cerebellar stroke. This study aimed to predict neurologic decline based on risk factors, volumetric analysis, and imaging characteristics. METHODS: This retrospective cohort study comprised patients ≥18 years who presented with acute cerebellar ischemic stroke (CIS) between January 2011 and December 2016. Diagnostic imaging was used to calculate metrics based on individual stroke, cerebellar, and posterior fossa volumes. Head computed tomography scans on presentation and day of peak swelling were used to tabulate a CIS score. RESULTS: The study included 86 patients; most were male and African American. Posterior inferior communicating artery stroke was most common (50%). On initial presentation imaging, 18.6% had documented hydrocephalus, 20.9% had brainstem compression, 22.1% had brainstem stroke, and 39.5% had stroke in another vascular territory. Cardioembolic stroke was the most common etiology, followed by cryptogenic stroke. Overall, patients who underwent surgical intervention had larger stroke volumes on presentation. Patients undergoing surgical intervention also experienced faster cerebellar swelling compared with patients without intervention. Total CIS scores were statistically significant and remained significant on the peak day of swelling. CIS score was independently associated with neurosurgical intervention; patients in this group with delayed interventions (median CIS score, 6; range, 4-8) later deteriorated and required emergent surgical decompression. Eleven patients without intervention had CIS score >6; 4 patients died of stroke complications. CONCLUSIONS: Volumetric studies and CIS score are objective measures that may help predict decline on imaging before clinical deterioration.

The Evolutionary Development of the Brain As It Pertains to Neurosurgery.

Background Neuroanatomists have long been fascinated by the complex topographic organization of the cerebrum. We examined historical and modern phylogenetic theories pertaining to microneurosurgical anatomy and intrinsic brain tumor development. Methods Literature and history related to the study of anatomy, evolution, and tumor predilection of the limbic and paralimbic regions were reviewed. We used vertebrate histological cross-sections, photographs from Albert Rhoton Jr.'s dissections, and original drawings to demonstrate the utility of evolutionary temporal causality in understanding anatomy. Results Phylogenetic neuroanatomy progressed from the substantial works of Alcmaeon, Herophilus, Galen, Vesalius, von Baer, Darwin, Felsenstein, Klingler, MacLean, and many others. We identified two major modern evolutionary theories: "triune brain" and topological phylogenetics. While the concept of "triune brain" is speculative and highly debated, it remains the most popular in the current neurosurgical literature. Phylogenetics inspired by mathematical topology utilizes computational, statistical, and embryological data to analyze the temporal transformations leading to three-dimensional topographic anatomy. These transformations have shaped well-defined surgical planes, which can be exploited by the neurosurgeon to access deep cerebral targets. The microsurgical anatomy of the cerebrum and the limbic system is redescribed by incorporating the dimension of temporal causality. Yasargil's anatomical classification of glial tumors can be revisited in light of modern phylogenetic cortical categorization. Conclusion Historical and modern topological phylogenetic notions provide a deeper understanding of neurosurgical anatomy and approaches to the limbic and paralimbic regions. However, many questions remain unanswered and further research is needed to elucidate the anatomical pathology of intrinsic brain tumors.

The Ultimate Skull Base Maneuver Does Not Involve Removing Bone: Quantifying the Benefits of the Interfascial Dissection.

Introduction Several adjunctive osteal skull base maneuvers have been proposed to increase surgical exposure of the anterolateral approach. However, one of the easiest methods does not involve bone: the interfascial temporalis muscle dissection. Methods Sequential dissections were performed bilaterally on five fixed silicone-injected cadaver heads. The amount of sphenoid drilling, scalp retraction, and brain retraction was standardized in all specimens. For each approach, surgical angles were measured for four deep targets: the tip of the anterior clinoid process, the internal carotid artery terminus, the origin of the posterior communicating artery, and the anterior communicating artery. Five surgical angles were measured for each target. Results There were increases on the order of 20% in the anteroposterior (AP)-mid, AP-lateral, and mediolateral-anterior angles for all deep targets with interfascial approach versus a myocutaneous flap. An orbitozygomatic osteotomy additionally increased almost all the angles, but incrementally less so. Conclusion An interfascial dissection increases the surgical exposure to a larger degree than additional osteotomies for several surgically relevant working angles. The addition of an orbitozygomatic osteotomy affords a particular benefit for the suprachiasmatic region. Increased adoption of interfascial mobilization or the temporalis muscle-an easily performed and low-risk maneuver-during anterolateral craniotomies may obviate the need for more involved skull base drilling.

Far Lateral Approach for Clipping of a Posterior Inferior Cerebellar Artery Aneurysm.

Objectives To describe a far lateral approach for microsurgical clipping of a ruptured posterior inferior cerebellar artery (PICA) aneurysm involving the hypoglossal nerve, with emphasis on the microsurgical anatomy, and technique. Design A far lateral craniotomy is performed in the lateral decubitus position and the transverse and sigmoid sinuses were exposed. After opening the dura, sutures are placed to allow gentle mobilization of the sinuses. The ipsilateral cerebellar tonsil is mobilized and the PICA is followed to its junction with the vertebral artery. Hypoglossal nerve rootlets are draped over the dome of the aneurysm. Mobilization of the PICA and the hypoglossal nerve away from the lateral medulla allows microsurgical clipping of the aneurysm neck. Photographs of the region are borrowed from Dr Rhoton's laboratory to illustrate the microsurgical anatomy. Participants The senior authors performed the surgery. The video was edited by Drs. V.N. and J.B. Chart review and literature review were performed by Drs. W.M. and J.B. Outcome Measures Outcome was assessed with successful clip occlusion and postoperative neurological function. Results There was complete clip occlusion of the PICA aneurysm with no postoperative neurological deficits. The patient was discharged home after an uneventful hospital course. Conclusion The far lateral approach provides an adequate corridor to the ventrolateral brainstem for microsurgical treatment of PICA aneurysms. An adequate understanding of the relevant microsurgical anatomy is the key to safe and effective clipping in this region. The link to the video can be found at: https://youtu.be/yhjKRIG5H74 .

Deconstruction of the Surgical Approach to the Jugular Foramen Region: Anatomical Study.

Introduction The jugular foramen occupies a complex and deep location between the skull base and the distal-lateral-cervical region. We propose a morphometric anatomical model to deconstruct its surgical anatomy and offer various quantifiable target-guided exposures and angles-of-attack. Methods Six cadaveric heads (12 sides) were dissected using a combined postauricular infralabyrinthine and distal transcervical approach with additional anterior transstyloid and posterior far lateral exposures. We identified anatomical landmarks and combined new and previously described contiguous triangles to expose the region; we defined the jugular and deep condylar triangles. Angles-of-attack to the jugular foramen were measured after removing the digastric muscle, styloid process, rectus capitis lateralis, and occipital condyle. Results Removing the digastric muscle and styloid process allowed 86.4° laterally and 85.5° anteriorly, respectively. Resecting the rectus capitis lateralis and jugular process provided the largest angle-of-attack (108.4° posteriorly). The occipital condyle can be drilled in the deep condylar triangle only adding 30.4° medially. A purely lateral approach provided a total of 280.3°. Cutting the jugular ring and mobilizing the vein can further expand the medial exposure. Conclusion The microsurgical anatomy of the jugular foramen can be deconstructed using a morphometric model, permitting a surgical approach customized to the pathology of interest.