Jesse Skoch

Integration of Indocyanine Green Videoangiography With Operative Microscope: Augmented Reality for Interactive Assessment of Vascular Structures and Blood Flow

BACKGROUND: Preservation of adequate blood flow and exclusion of flow from lesions are key concepts of vascular neurosurgery. Indocyanine green (ICG) fluorescence videoangiography is now widely used for the intraoperative assessment of vessel patency. OBJECTIVE: Here, we present a proof-of-concept investigation of fluorescence angiography with augmented microscopy enhancement: real-time overlay of fluorescence videoangiography within the white light field of view of conventional operative microscopy. METHODS: The femoral artery was exposed in 7 anesthetized rats. The dissection microscope was augmented to integrate real-time electronically processed near-infrared filtered images with conventional white light images seen through the standard oculars. This was accomplished by using an integrated organic light-emitting diode display to yield superimposition of white light and processed near-infrared images. ICG solution was injected into the jugular vein, and fluorescent femoral artery flow was observed. RESULTS: Fluorescence angiography with augmented microscopy enhancement was able to detect ICG fluorescence in a small artery of interest. Fluorescence appeared as a bright-green signal in the ocular overlaid with the anatomic image and limited to the anatomic borders of the femoral artery and its branches. Surrounding anatomic structures were clearly visualized. Observation of ICG within the vessel lumens permitted visualization of the blood flow. Recorded video loops could be reviewed in an offline mode for more detailed assessment of the vasculature. CONCLUSION: The overlay of fluorescence videoangiography within the field of view of the white light operative microscope allows real-time assessment of the blood flow within vessels during simultaneous surgical manipulation. This technique could improve intraoperative decision making during complex neurovascular procedures. ABBREVIATIONS: DSA, digital subtraction angiography FAAME, fluorescence angiography with augmented microscopy enhancement ICG, indocyanine green NIR, near-infrared OLED, organic light-emitting diode

The surgical neurovascular anatomy relating to partial and complete sacral and sacroiliac resections: a cadaveric, anatomic study

PurposePelvic and sacral surgeries are considered technically difficult due to the complex multidimensional anatomy and the presence of significant neurovascular structures. Knowledge of the key neurovascular anatomy is essential for safe and effective execution of partial and complete sacral resections. The goal of this anatomic, cadaveric study is to describe the pertinent neurovascular anatomy during these procedures.MethodsThree embalmed human cadaveric specimens were used. Sacrectomies and sacroiliac joint resections were simulated and the structures at risk were identified. Both anterior and posterior approaches were evaluated.ResultsDuring sacroiliac joint resection, L5 nerve roots are at high risk for iatrogenic injury; the vasculatures at greatest risk are the common iliac vessels and internal iliac vessels with L5–S1 and S1–S2 high sacrectomies. Minor bleeding risk is associated with S2–S3 osteotomy because of the potential to damage superior gluteal vessels. S3–S4 osteotomy presents a low risk of bleeding. Adjacent nerve roots proximal to the resection level are at high risk during higher sacrectomies.ConclusionsSeveral sacrectomy techniques are available and selection often depends on the specific case and surgeon preference; nevertheless, anatomic knowledge is extremely important. Considering the highly variable anatomic relations of the vascular bundles, a preoperative evaluation with CT or MRI with vascular reconstruction may be helpful to decrease bleeding risk by preemptively binding the internal iliac vessels in cases where higher tumors are present. To decrease the risk of damaging nerve roots, it is recommended to perform the resection as close to the involved foramina as possible.

A paradigm for the evaluation and management of spinal coccidioidomycosis

Background: Coccidioidomycosis is a fungal infection that is endemic to parts of the Southwestern United States. When infection involves the spine, the treatment strategies can be challenging. We have devised a management protocol for spinal coccidioidomycosis based on a review of the literature and our experience. Methods: The electronic literature search of National Library of Medicine for publications from 1964 to 2014 was performed using the following keywords: Coccidioidomycosis and spine. The search yielded 24 papers. Treatment strategies were summarized into a treatment protocol. Results: A total of 164 cases of spinal coccidioidomycosis were identified, ranging in age from <10 to >80 years. Males (n = 131) and African-Americans (n = 79) were strikingly over-represented. Medical therapy: Once a diagnosis of spinal coccidioidomycosis is established, antifungal therapy should always be started. Antifungal therapy with amphotericin B or azoles like fluconazole. Medical therapy needs to be continued for many years and sometimes indefinitely to reduce disease recurrence or progression. Surgical management is indicated in cases with mechanical instability, neurologic deficit, medically intractable pain, or progression of infection despite antifungal therapy. Conclusions: This work provides a working protocol involving assessment and reassessment for the management of spinal coccidioidomycosis. Medical management with antifungal agents in some cases can provide satisfactory disease control. However, in patients with mechanical instability, neurologic deficit, medically intractable pain or disease progression disease control may only be achieved with surgical debridement and stabilization.

Freehand thoracic pedicle screw technique using a uniform entry point and sagittal trajectory for all levels: preliminary clinical experience

OBJECT Experience with freehand thoracic pedicle screw placement is well described in the literature. Published techniques rely on various starting points and trajectories for each level or segment of the thoracic spine. Furthermore, few studies provide specific guidance on sagittal and axial trajectories. The goal of this study was to propose a uniform entry point and sagittal trajectory for all thoracic levels during freehand pedicle screw placement and determine the accuracy of this technique. METHODS The authors retrospectively reviewed postoperative CT scans of 33 consecutive patients who underwent open, freehand thoracic pedicle-screw fixation using a uniform entry point and sagittal trajectory for all levels. The same entry point for each level was defined as a point 3 mm caudal to the junction of the transverse process and the lateral margin of the superior articulating process, and the sagittal trajectory was always orthogonal to the dorsal curvature of the spine at that level. The medial angulation (axial trajectory) was approximately 30° at T-1 and T-2, and 20° from T-3 to T-12. Breach was defined as greater than 25% of the screw diameter residing outside of the pedicle or vertebral body. RESULTS A total of 219 thoracic pedicle screws were placed with a 96% accuracy rate. There were no medial breaches and 9 minor lateral breaches (4.1%). None of the screws had to be repositioned postoperatively, and there were no neurovascular complications associated with the breaches. CONCLUSIONS It is feasible to place freehand thoracic pedicle screws using a uniform entry point and sagittal trajectory for all levels. The entry point does not have to be adjusted for each level as reported in existing studies, although this technique was not tested in severe scoliotic spines. While other techniques are effective and widely used, this particular method provides more specific parameters and may be easier to learn, teach, and adopt.

Surgical anatomy of the minimally invasive lateral lumbar approach.

The lateral lumbar interbody fusion approach (LLIF), which encompasses the extreme lateral interbody fusion or direct lateral interbody fusion techniques, has gained popularity as an alternative to traditional posterior approaches. With rapidly expanding applications, this minimally invasive surgery (MIS) approach is now utilized in basic degenerative pathologies as well as complex lumbar degenerative deformities and tumors. Given the intimate relationship of the psoas muscle, and hence the lumbar plexus, to this MIS approach, several authors have examined the surgical anatomy of this approach. Understanding this regional neural anatomy is imperative given the potential for serious injuries to both the motor and sensory nerves of the lumbar plexus. In this review, we critically and comprehensively discuss all published studies detailing the surgical anatomy of the lateral lumbar approach with respect to the MIS LLIF techniques. This is a timely review given the rapidly growing number of surgeons utilizing this technique.

Augmented microscopy: real-time overlay of bright-field and near-infrared fluorescence images

Abstract. Intraoperative applications of near-infrared (NIR) fluorescent contrast agents can be aided by instrumentation capable of merging the view of surgical field with that of NIR fluorescence. We demonstrate augmented microscopy, an intraoperative imaging technique in which bright-field (real) and electronically processed NIR fluorescence (synthetic) images are merged within the optical path of a stereomicroscope. Under luminance of 100,000 lx, representing typical illumination of the surgical field, the augmented microscope detects 189 nM concentration of indocyanine green and produces a composite of the real and synthetic images within the eyepiece of the microscope at 20 fps. Augmentation described here can be implemented as an add-on module to visualize NIR contrast agents, laser beams, or various types of electronic data within the surgical microscopes commonly used in neurosurgical, cerebrovascular, otolaryngological, and ophthalmic procedures.

Bracing After Surgical Stabilization of Thoracolumbar Fractures: A Systematic Review of Evidence, Indications, and Practices.

BACKGROUND The role of spinal orthotic braces after surgical stabilization is not clearly defined. We systematically reviewed the published literature to determine patterns of practice, indications, and current evidence for the use of orthotic braces after surgical thoracolumbar fracture stabilization. METHODS A search was performed for publications including descriptions of postoperative management and outcomes after surgical stabilization of thoracolumbar injuries. Differences between wearing versus not wearing a postoperative brace were examined with regard to loss of deformity correction, pain, return to previous work activity, functional improvement, instrumentation failure rate, pseudoarthrosis, and the percentage of reported complications. RESULTS This search yielded 76 pertinent studies. Postoperative bracing (POB) was adopted in 62 studies for a median wear time of 13.3 weeks. No significant differences in terms of pain, return to work, Frankel score improvement, or instrumentation failure were found between the POB and non-POB groups. Loss of surgical kyphotic reduction was slightly greater in the POB group (4.79° vs. 3.77°; P < 0.001). The overall complication rate was also higher in the POB group (16.3% vs. 11.9%; P < 0.01). The pseudoarthrosis rate was lower in the braced group (2.4% vs. 6.0%; P < 0.001). CONCLUSIONS Most surgeons use braces for 3 months after surgical thoracolumbar fracture stabilization. Given the lack of clinical or biomechanical evidence for this, and the additional costs and potential discomfort to patients, further investigation is warranted to determine when and if POB for surgically stabilized thoracolumbar fractures is indicated. Controlled studies should include a careful analysis of pseudoarthrosis and complication rates.

Posterior atlantoaxial fixation: A cadaveric and fluoroscopic step-by-step technical guide.

Background: Atlantoaxial surgical fixation is widely employed treatment strategy for a myriad of pathologies affecting the stability of the atlantoaxial joint. The most common technique used in adults, and in certain cases in children, involves a posterior construct with C1 lateral mass screws, and C2 pars or pedicle screws. This technical note aims to provide a step-by-step guide to this procedure using cadaveric and fluoroscopic images. Methods: An embalmed, human, cadaveric, specimen was used for this study. The subject did not have obvious occipital-cervical pathology. Dissections and techniques were performed to mimic actual surgical technique. Photographs were taken during each step, and the critical aspects of each step were highlighted. Fluoroscopic images from a real patient undergoing C1/C2 fixation were also utilized to further highlight the anatomic-radiographic relationships. This study was performed without external or industry funding. Results: Photographic and radiographic pictures and drawings are presented to illustrate the pertinent anatomy and technical aspects of this technique. The nuances of each step, including complication avoidance strategies are also highlighted. Conclusions: Given the widespread utilization of this technique, described step-by-step guide is timely for surgeons and trainees alike.

Posterior longitudinal ligament resection or preservation in anterior cervical decompression surgery

We reviewed the literature to determine differences in clinical outcomes for the removal or preservation of the posterior longitudinal ligament (PLL) in anterior cervical discectomy and fusion (ACDF). The outcomes are surgeon and case-dependent for both practices. A literature review was performed in PubMed from the years 1960 to 2014 to identify studies describing surgeries where the PLL was removed or preserved during ACDF. Searches were performed using Medical Subject Headings (MeSH) and references included in the reviewed articles were also considered. Additionally we searched recent articles that cited those from the original search. The search yielded 79 articles and 115 pertinent citations. These 194 articles were reviewed for specific discussions of PLL resection or preservation. Four articles containing 122 patients were included in the final analysis. In 69 patients the PLL was removed and in 53 the PLL was preserved. Both groups improved in clinical scores during follow up. One patient in the PLL removal group had a cerebrospinal fluid leak. MRI and correlative outcome data suggest that a non-ossified PLL itself does not contribute to significant cord compression. Postoperative MRI of patients with the PLL removed showed a larger spinal cord diameter. Resection of the PLL is safe and common in ACDF surgery but there does not appear to be a demonstrable clinical difference in patients where it is resected. The ultimate decision is likely surgeon and case-dependent. Randomized trials could further determine the importance of PLL removal in ACDF treated patients.

Anatomic considerations of the anterior upper cervical spine during decompression and instrumentation: A cadaveric based study

We evaluated the anatomical considerations specific to the high anterior retropharyngeal approach to the cervical spine. Surgical exposure of the anterior upper cervical spine can sometimes be challenging due to the surrounding neurovascular structures. Using three adult cadavers, we performed high anterior retropharyngeal cervical dissection of the left and right side for a total of six approaches (six sides). During the dissection, all important neurovascular elements were noted and photographed, and anatomical relationships to the spinal vertebral bodies and disc spaces were analyzed. There are certain anatomic considerations that are unique to the high anterior cervical spine. The unique structures include the hypoglossal nerve and the superior thyroid artery/nerve. Only the superior thyroid artery in this region has numerous anatomical variations. Awareness of other structures, including the carotid artery, recurrent laryngeal nerve, and esophagus also remains important. Awareness of the anatomical structures in the anterior upper cervical spine is essential for performing safe anterior upper cervical spinal surgery, avoiding serious complications.