Randall A. Bly

Computer-Guided Orbital Reconstruction to Improve Outcomes

OBJECTIVES (1) To describe repair of complex orbital fractures using computer planning with preoperative virtual reconstruction, mirror image overlay, endoscopy, and surgical navigation. (2) To test the hypothesis that this technique improves outcomes in complex orbital fractures. METHODS A series of 113 consecutive severe orbital fracture cases was analyzed, 56 of which were performed with mirror image overlay guidance, and 57 of which were repaired without. Data were collected on patient characteristics, fracture severity, diplopia and globe position outcomes, complications, and need for revision surgery. RESULTS The mirror image overlay group showed decreased postoperative diplopia in all fracture types (P = .003); the effectiveness was maximal for fractures that involved 3 or 4 walls or the posterior one-third of the orbital floor (P < .001). The need for revision surgery was greatly reduced in this cohort (4% vs 20%; P = .03). CONCLUSIONS The efficacy of mirror image overlay navigation and orbital endoscopy was studied in one of the largest series of complex orbital fractures in the literature. Based on statistically significant improved outcomes in postoperative diplopia and orbital volume, as well as the decreased need for revision surgery, we accept the hypothesis that mirror image overlay guidance improves outcomes in complex orbital reconstruction and recommend its use for complex orbital fracture repair.

Lateral Transorbital Neuroendoscopic Approach to the Lateral Cavernous Sinus

Objective To design and assess the quality of a novel lateral retrocanthal endoscopic approach to the lateral cavernous sinus. Design Computer modeling software was used to optimize the geometry of the surgical pathway, which was confirmed on cadaver specimens. We calculated trajectories and surgically accessible areas to the middle fossa while applying a constraint on the amount of soft tissue retraction. Setting Virtual computer model to simulate the surgical approach and cadaver laboratory. Participants The authors. Main Outcome Measures Adequate surgical access to the lateral cavernous sinus and adjacent regions as determined by operations on the cadaver specimens. Additionally, geometric limitations were imposed as determined by the model so that retraction on soft tissue structures was maintained at a clinically safe distance. Results Our calculations revealed adequate access to the lateral cavernous sinus, Meckel cave, orbital apex, and middle fossa floor. Cadaveric testing revealed sufficient access to these areas using <10 mm of orbital retraction. Conclusions Our study validates not only the use of computer simulation to plan operative approaches but the feasibility of the lateral retrocanthal approach to the lateral cavernous sinus.

Transorbital neuroendoscopic surgery for the treatment of skull base lesions

Transorbital neuroendoscopic surgery (TONES) is a relatively new technique that not only allows access to the contents of the orbit but also the intracranial compartment, including the anterior cranial fossa, middle fossa and lateral cavernous sinus. In this study, we aimed to retrospectively review the largest experience to our knowledge with regards to surgical outcomes of skull base pathologies treated with a TONES procedure. Forty patients (aged 3-89 years) underwent 45 TONES procedures between the years of 2006-2013. Pathologies were cerebrospinal fluid leak repair (n=16), traumatic fracture (n=8), tumor (n=11), meningoencephalocele (n=5), hematoma (n=1), and infection (n=4). Three patients had a persistent complication at 3 months, including a case each of enophthalmos (unnoticed by patient), epiphora (delayed presentation at 2 months requiring dacryocystorhinostomy), and ptosis (improved at 1 year). Surgical success was achieved in all patients. Of special import, there were no cases of visual decline, diplopia, or stroke. There was no mortality. To our knowledge this is the first study and largest experience of TONES (level 4 evidence) to detail outcomes with respect to skull base pathologies. Our results indicate that TONES procedures can be performed with minimal morbidity. Further studies are needed to assess equivalency with craniotomy based approaches though this initial report is encouraging.

Computer Modeled Multiportal Approaches to the Skull Base

Skull base surgical approaches have evolved significantly to minimize collateral tissue damage and improve access to complex anatomic regions. Many endoscopic surgical portals have been described, and these can be combined in multiportal approaches that permit improved angles for visualization and instrumentation. To assist in the choice of entry portal and surgical pathway analysis, a three-dimensional computer model with virtual endoscopy was created. The model was evaluated on transnasal and transorbital approaches to access 11 specified sellar and parasellar target locations on 14 computed tomography (CT) scans. Data were collected on length of approach, angle between instruments, and approach angle with respect to anatomical planes. Optimal multiportal approach combinations were derived. The data demonstrated that the shortest, most direct pathway to many sellar and parasellar targets was through transorbital portals. Distances were reduced by 35% for certain target locations; combining transorbital and transnasal portals increased the angle between instruments 4-fold for many targets. The predicted values from the model were validated on four cadaver specimens. Computer modeling holds the potential to play an integral role in the design, analysis, and testing of new surgical approaches, as well as in the selection of optimal approach strategies for the unique pathology of individual patients.

Multiportal Robotic Access to the Anterior Cranial Fossa: A Surgical and Engineering Feasibility Study

Objective Integration of robotic surgical technology into skull base surgery is limited due to minimum angle requirements between robotic tools (narrow funnel effect), steep angle of approach, and instrumentation size. The objectives of this study were to systematically analyze surgical approach portals using a computer model, determine optimal approaches, and assess feasibility of the derived approaches on robotic surgical systems. Study Design Computer analysis on 10 computed tomography scans was performed to determine approach trajectories, angles between robotic tools, and distances to specified skull base target locations for transorbital and transnasal surgical approach portals. Setting Dry laboratory and cadaver laboratory. Subjects and Methods The optimal combinations were tested on the da Vinci and Raven robotic systems. Results Multiportal analyses showed the angles between 2 robotic tools were 14.7, 28.3, and 52.0 degrees in the cases of 2 transnasal portals, combined transnasal and medial orbit portals, and bilateral superior orbit portals, respectively, approaching a prechiasmatic target. The addition of medial and superior transorbital portals improved the skull base trajectory angles 21 and 27 degrees, respectively. Two robotic tools required an angle of at least 20 degrees between them to function effectively at skull base targets. Conclusion Technical feasibility of robotic transorbital and transnasal approaches to access sella and parasellar target locations was demonstrated. This technique addresses the 2 major drawbacks of (1) the narrow funnel effect generated from portals in close proximity and (2) the steep angle of approach to the skull base, as observed in previous studies analyzing transoral, transcervical, transmaxillary, and transhyoid portals.

Tension Pneumocephalus after Endoscopic Sinus Surgery

Objectives:Large skull base defects and cerebrospinal fluid (CSF) leak repairs are traditionally performed through a transnasal endoscopic approach or an open craniotomy approach. While this is often successful, when the defect is adjacent to the crista galli it can be very difficult to seal the medial portions of the defect. Our objective is to report our experience using a novel multiportal (transnasal and transorbital) endoscopic technique to repair large, bilateral anterior cranial fossae defects using an intracranial “brain sling.”Methods:Reviews of the literature and medical records were performed.Results:Endoscopic transnasal and transorbital repair of large bilateral anterior cranial fossae skull base defects was performed using acellular radiated cadaver dermis and collagen matrix through a multiportal approach. The visualization and surgical access through transorbital portals permitted an intracranial extradural/intradural repair using a single, large section of reconstruction material. It was ...

An Automated Methodology for Assessing Anatomy-Specific Instrument Motion during Endoscopic Endonasal Skull Base Surgery

Objectives Describe instrument motion during live endoscopic skull base surgery (ESBS) and evaluate kinematics within anatomic regions. Design Case series. Setting Tertiary academic center. Participants A single skull base surgeon performed six anterior skull base approaches to the pituitary. Main Outcomes and Measures Time‐stamped instrument coordinates were recorded using an optical tracking system. Kinematics (i.e., mean cumulative instrument travel, velocity, acceleration, and angular velocity) was calculated by anatomic region including nasal vestibule, anterior and posterior ethmoid, sphenoid, and lateral opticocarotid recess (lOCR) regions. Results We observed mean (standard deviation, SD) velocities of 6.14 cm/s (1.55) in the nasal vestibule versus 1.65 cm/s (0.34) near the lOCR. Mean (SD) acceleration was 7,480 cm/s2 (5790) in the vestibule versus 928 cm/s2 (662) near the lOCR. Mean (SD) angular velocity was 17.2 degrees/s (8.31) in the vestibule and 5.37 degrees/s (1.09) near the lOCR. We observed a decreasing trend in the geometric mean velocity, acceleration, and angular velocity when approaching the pituitary (p < 0.001). Conclusion Using a novel method for analyzing instrument motion during live ESBS, we observed a decreasing trend in kinematics with proximity to the pituitary. Additional characterization of surgical instrument motion is paramount for optimizing patient safety and training.

Tension pneumocephalus after endoscopic sinus surgery: a technical report of multiportal endoscopic skull base repair.

Objectives: Large skull base defects and cerebrospinal fluid (CSF) leak repairs are traditionally performed through a transnasal endoscopic approach or an open craniotomy approach. While this is often successful, when the defect is adjacent to the crista galli it can be very difficult to seal the medial portions of the defect. Our objective is to report our experience using a novel multiportal (transnasal and transorbital) endoscopic technique to repair large, bilateral anterior cranial fossae defects using an intracranial “brain sling.” Methods: Reviews of the literature and medical records were performed. Results: Endoscopic transnasal and transorbital repair of large bilateral anterior cranial fossae skull base defects was performed using acellular radiated cadaver dermis and collagen matrix through a multiportal approach. The visualization and surgical access through transorbital portals permitted an intracranial extradural/intradural repair using a single, large section of reconstruction material. It was introduced through a portal distant to the site of injury to avoid enlarging the region of damage, and fashioned so that forces of gravity maintained its proper position. All leaks were repaired successfully with one surgical procedure, and there were no surgical complications in the cohort. Conclusions: The “brain sling” technique is applicable to the reconstruction of large skull base defects of any etiology and may be important for oncologic reconstruction. By using a multiportal approach, instrumentation could be performed without blocking the endoscopic view, and multiple viewing angles of the pathology could be used to improve the surgical efficacy.

Head and Neck Lymphatic Malformation Diagnosis and Treatment

Diagnosis of head and neck lymphatic malformation (HNLM) has changed over time from pure description to detection of their molecular cause (Luks et al, J Pediatr 166(4):1048–54. e1–5, 2015; Perkins et al, Otolaryngol Head Neck Surg 142(6):789–794, 2010). Nomenclature used to describe HNLM has broadened from “cystic hygroma” and “lymphangioma” to malformation, as evidence for continued use of these terms is not apparent (Perkins et al, Otolaryngol Head Neck Surg 142(6):789–794, 2010). This is most apparent in HNLM prenatal diagnosis where in utero ultrasound imaging detects HNLM (Longstreet et al, Otolaryngol Head Neck Surg 52(2):342–347, 2015) (Fig. 20.1). In the perinatal literature, soft-tissue lucency and thickening in the posterior/dorsal neck are still called “cystic hygroma” and are associated with increased risk for abnormal fetal karyotype (Malone et al, Obstet Gynecol 106(2):288–294, 2005). Now the widely available highly sensitive and specific noninvasive prenatal testing (NIPT) can detect abnormal karyotypes and specific genetically determined syndromes (i.e., Noonan) from fetal DNA in maternal blood, without invasive testing (Grande et al, Ultrasound Obstet Gynecol 46(6):650–658, 2015). This shift in our understanding on maternal-fetal physiology and our ability to detect differences between circulating fetal and maternal DNA has also changed our understanding of in utero ultrasound detected large fluid-filled spaces in the head and neck, so we know that they are a result of molecular changes in DNA and not just “watery tumors” or “lymph tumors.” As investigation into the cause and nature of HNLM has occurred, it is felt that “malformation” is a more accurate way of categorizing these lesions.

Medical Management of Vascular Anomalies

Purpose of reviewThis chapter will summarize the most recent literature regarding the current state of medical treatment for vascular anomalies.Recent findingsResearch into the biology of these anomalies has strengthened our understanding of each anomaly and has helped to pave the way for more tailored treatment options involving molecular and/or genetic targets.SummaryWhile there is still a role for surgical intervention, medical therapies that target the etiology of vascular anomalies may represent an alternative or adjunctive approach in the management of these lesions.