Intraoperative in vivo confocal endomicroscopy of the glioma margin: performance assessment of image interpretation by neurosurgeon users.

Objectives: Confocal laser endomicroscopy (CLE) is an intraoperative real-time cellular resolution imaging technology that images brain tumor histoarchitecture. Previously, we demonstrated that CLE images may be interpreted by neuropathologists to determine the presence of tumor infiltration at glioma margins. In this study, we assessed neurosurgeons' ability to interpret CLE images from glioma margins and compared their assessments to those of neuropathologists. Methods: In vivo CLE images acquired at the glioma margins that were previously reviewed by CLE-experienced neuropathologists were interpreted by four CLE-experienced neurosurgeons. A numerical scoring system from 0 to 5 and a dichotomous scoring system based on pathological features were used. Scores from assessments of hematoxylin and eosin (H&E)-stained sections and CLE images by neuropathologists from a previous study were used for comparison. Neurosurgeons' scores were compared to the H&E findings. The inter-rater agreement and diagnostic performance based on neurosurgeons' scores were calculated. The concordance between dichotomous and numerical scores was determined. Results: In all, 4275 images from 56 glioma margin regions of interest (ROIs) were included in the analysis. With the numerical scoring system, the inter-rater agreement for neurosurgeons interpreting CLE images was moderate for all ROIs (mean agreement, 61%), which was significantly better than the inter-rater agreement for the neuropathologists (mean agreement, 48%) (p < 0.01). The inter-rater agreement for neurosurgeons using the dichotomous scoring system was 83%. The concordance between the numerical and dichotomous scoring systems was 93%. The overall sensitivity, specificity, positive predictive value, and negative predictive value were 78%, 32%, 62%, and 50%, respectively, using the numerical scoring system and 80%, 27%, 61%, and 48%, respectively, using the dichotomous scoring system. No statistically significant differences in diagnostic performance were found between the neurosurgeons and neuropathologists. Conclusion: Neurosurgeons' performance in interpreting CLE images was comparable to that of neuropathologists. These results suggest that CLE could be used as an intraoperative guidance tool with neurosurgeons interpreting the images with or without assistance of the neuropathologists. The dichotomous scoring system is robust yet simple and may streamline rapid, simultaneous interpretation of CLE images during imaging.

Intraoperative in vivo confocal laser endomicroscopy imaging at glioma margins: can we detect tumor infiltration?

OBJECTIVE: Confocal laser endomicroscopy (CLE) is a US Food and Drug Administration-cleared intraoperative real-time fluorescence-based cellular resolution imaging technology that has been shown to image brain tumor histoarchitecture rapidly in vivo during neuro-oncological surgical procedures. An important goal for successful intraoperative implementation is in vivo use at the margins of infiltrating gliomas. However, CLE use at glioma margins has not been well studied. METHODS: Matching in vivo CLE images and tissue biopsies acquired at glioma margin regions of interest (ROIs) were collected from 2 institutions. All images were reviewed by 4 neuropathologists experienced in CLE. A scoring system based on the pathological features was implemented to score CLE and H&E images from each ROI on a scale from 0 to 5. Based on the H&E scores, all ROIs were divided into a low tumor probability (LTP) group (scores 0-2) and a high tumor probability (HTP) group (scores 3-5). The concordance between CLE and H&E scores regarding tumor probability was determined. The intraclass correlation coefficient (ICC) and diagnostic performance were calculated. RESULTS: Fifty-six glioma margin ROIs were included for analysis. Interrater reliability of the scoring system was excellent when used for H&E images (ICC [95% CI] 0.91 [0.86-0.94]) and moderate when used for CLE images (ICC [95% CI] 0.69 [0.40-0.83]). The ICCs (95% CIs) of the LTP group (0.68 [0.40-0.83]) and HTP group (0.68 [0.39-0.83]) did not differ significantly. The concordance between CLE and H&E scores was 61.6%. The sensitivity and specificity values of the scoring system were 79% and 37%. The positive predictive value (PPV) and negative predictive value were 65% and 53%, respectively. Concordance, sensitivity, and PPV were greater in the HTP group than in the LTP group. Specificity was higher in the newly diagnosed group than in the recurrent group. CONCLUSIONS: CLE may detect tumor infiltration at glioma margins. However, it is not currently dependable, especially in scenarios where low probability of tumor infiltration is expected. The proposed scoring system has excellent intrinsic interrater reliability, but its interrater reliability is only moderate when used with CLE images. These results suggest that this technology requires further exploration as a method for consistent actionable intraoperative guidance with high dependability across the range of tumor margin scenarios. Specific-binding and/or tumor-specific fluorophores, a CLE image atlas, and a consensus guideline for image interpretation may help with the translational utility of CLE.

Intraoperative confocal laser endomicroscopy: prospective in vivo feasibility study of a clinical-grade system for brain tumors.

OBJECTIVE: The authors evaluated the feasibility of using the first clinical-grade confocal laser endomicroscopy (CLE) system using fluorescein sodium for intraoperative in vivo imaging of brain tumors. METHODS: A CLE system cleared by the FDA was used in 30 prospectively enrolled patients with 31 brain tumors (13 gliomas, 5 meningiomas, 6 other primary tumors, 3 metastases, and 4 reactive brain tissue). A neuropathologist classified CLE images as interpretable or noninterpretable. Images were compared with corresponding frozen and permanent histology sections, with image correlation to biopsy location using neuronavigation. The specificities and sensitivities of CLE images and frozen sections were calculated using permanent histological sections as the standard for comparison. A recently developed surgical telepathology software platform was used in 11 cases to provide real-time intraoperative consultation with a neuropathologist. RESULTS: Overall, 10,713 CLE images from 335 regions of interest were acquired. The mean duration of the use of the CLE system was 7 minutes (range 3-18 minutes). Interpretable CLE images were obtained in all cases. The first interpretable image was acquired within a mean of 6 (SD 10) images and within the first 5 (SD 13) seconds of imaging; 4896 images (46%) were interpretable. Interpretable image acquisition was positively correlated with study progression, number of cases per surgeon, cumulative length of CLE time, and CLE time per case (p ≤ 0.01). The diagnostic accuracy, sensitivity, and specificity of CLE compared with frozen sections were 94%, 94%, and 100%, respectively, and the diagnostic accuracy, sensitivity, and specificity of CLE compared with permanent histological sections were 92%, 90%, and 94%, respectively. No difference was observed between lesion types for the time to first interpretable image (p = 0.35). Deeply located lesions were associated with a higher percentage of interpretable images than superficial lesions (p = 0.02). The study met the primary end points, confirming the safety and feasibility and acquisition of noninvasive digital biopsies in all cases. The study met the secondary end points for the duration of CLE use necessary to obtain interpretable images. A neuropathologist could interpret the CLE images in 29 (97%) of 30 cases. CONCLUSIONS: The clinical-grade CLE system allows in vivo, intraoperative, high-resolution cellular visualization of tissue microstructure and identification of lesional tissue patterns in real time, without the need for tissue preparation.

Rare Giant Infected Intradiploic Skull Epidermoid Cysts.

Infections associated with giant intradiploic cranial epidermoid cysts are rare. This case report describes the successful surgical management of a 71-year-old diabetic man with a giant intradiploic cranial epidermoid cyst associated with a secondary infection. The patient underwent successful resection of the infected lesion with washout, debridement, and obliteration of the eustachian canal and external auditory canal. At the six-month follow-up, the infection was resolved and the patient was doing well clinically. Intradiploic epidermoid cysts are rare, and the presence of a superimposed otogenic infection is exceptionally rare and infrequently reported in the neurosurgical literature.

Single-Position Anterior and Lateral Lumbar Fusion in the Supine Position: A Novel Technique for Multilevel Arthrodesis.

OBJECTIVE: Anterior lumbar interbody fusion (ALIF) and lateral lumbar interbody fusion are common techniques that typically require staged procedures when performed in combination. Interest is emerging in single-position surgery to increase operative efficiency. We report a novel surgical technique, supine extended reach lateral fusion, to perform ALIF and lateral lumbar interbody fusion with the patient in a single supine position. METHODS: A man in his fifties presented with degenerative levoscoliosis, spondylolisthesis, sagittal plane deformity, and progressive low back pain. He was offered L3-S1 anterolateral fusion. RESULTS: With the patient supine, a left abdominal paramedian incision was performed to gain anterior retroperitoneal access, and standard L5-S1 and L4-5 ALIFs were performed. The anterior incision was used for direct visualization, retraction, and bimanual dissection. A left lateral incision was then made to perform an L3-4 lateral lumbar interbody fusion. He subsequently underwent a second-stage L3-S1 posterior percutaneous fixation. The patient tolerated the procedures well, without complications. His postoperative radiograph findings confirmed acceptable implant positioning. He was discharged home in stable condition and was doing well at follow-up. CONCLUSIONS: This case description is the first report of the supine extended reach technique, which allows incorporation of anterior and lateral fusion constructs at adjacent levels without changing patient positioning. Many surgeons believe the ALIF to be the most powerful technique for achieving lordosis, and this technique enables concomitant lateral access in a supine position. It can also be used as an alternative strategy when anterior access to the disc space is unobtainable. Further clinical investigation of this technique is warranted.

Real-time intraoperative surgical telepathology using confocal laser endomicroscopy.

OBJECTIVE: Communication between neurosurgeons and pathologists is mandatory for intraoperative decision-making and optimization of resection, especially for invasive masses. Handheld confocal laser endomicroscopy (CLE) technology provides in vivo intraoperative visualization of tissue histoarchitecture at cellular resolution. The authors evaluated the feasibility of using an innovative surgical telepathology software platform (TSP) to establish real-time, on-the-fly remote communication between the neurosurgeon using CLE and the pathologist. METHODS: CLE and a TSP were integrated into the surgical workflow for 11 patients with brain masses (6 patients with gliomas, 3 with other primary tumors, 1 with metastasis, and 1 with reactive brain tissue). Neurosurgeons used CLE to generate video-flow images of the operative field that were displayed on monitors in the operating room. The pathologist simultaneously viewed video-flow CLE imaging using a digital tablet and communicated with the surgeon while physically located outside the operating room (1 pathologist was in another state, 4 were at home, and 6 were elsewhere in the hospital). Interpretations of the still CLE images and video-flow CLE imaging were compared with the findings on the corresponding frozen and permanent H&E histology sections. RESULTS: Overall, 24 optical biopsies were acquired with mean ± SD 2 ± 1 optical biopsies per case. The mean duration of CLE system use was 1 ± 0.3 minutes/case and 0.25 ± 0.23 seconds/optical biopsy. The first image with identifiable histopathological features was acquired within 6 ± 0.1 seconds. Frozen sections were processed within 23 ± 2.8 minutes, which was significantly longer than CLE usage (p < 0.001). Video-flow CLE was used to correctly interpret tissue histoarchitecture in 96% of optical biopsies, which was substantially higher than the accuracy of using still CLE images (63%) (p = 0.005). CONCLUSIONS: When CLE is employed in tandem with a TSP, neurosurgeons and pathologists can view and interpret CLE images remotely and in real time without the need to biopsy tissue. A TSP allowed neurosurgeons to receive real-time feedback on the optically interrogated tissue microstructure, thereby improving cross-functional communication and intraoperative decision-making and resulting in significant workflow advantages over the use of frozen section analysis.

Introduction of In Vivo Confocal Laser Endomicroscopy and Real-Time Telepathology for Remote Intraoperative Neurosurgery-Pathology Consultation.

BACKGROUND: Precise communication between neurosurgeons and pathologists is crucial for optimizing patient care, especially for intraoperative diagnoses. Confocal laser endomicroscopy (CLE) combined with a telepathology software platform (TSP) provides a novel venue for neurosurgeons and pathologists to review CLE images and converse intraoperatively in real-time. OBJECTIVE: To describe the feasibility of integrating CLE and a TSP in the surgical workflow for real-time review of in vivo digital fluorescence tissue imaging in 3 patients with intracranial tumors. METHODS: Although the neurosurgeon used the CLE probe to generate fluorescence images of histoarchitecture within the operative field that were displayed on monitors in the operating room, the pathologist simultaneously remotely viewed the CLE images. The neurosurgeon and pathologist discussed in real-time the histological structures of intraoperative imaging locations. RESULTS: The neurosurgeon placed the CLE probe at various locations on and around the tumor, in the surgical resection bed, and on surrounding brain tissue with communication through the TSP. The neurosurgeon oriented the pathologist to the location of the CLE, and the pathologist and neurosurgeon discussed the CLE images in real-time. The TSP and CLE were integrated successfully and rapidly in the operating room in all 3 cases. No patient had perioperative complications. CONCLUSION: Two novel digital neurosurgical cellular imaging technologies were combined with intraoperative neurosurgeon-pathologist communication to guide the identification of abnormal histoarchitectural tissue features in real-time. CLE with the TSP may allow rapid decision-making during tumor resection that may hold significant advantages over the frozen section process and surgical workflow in general.

Perioperative Complication Profile of Skull Base Meningioma Resection in Older versus Younger Adult Patients.

Objectives To better understand the risk-benefit profile of skull base meningioma resection in older patients, we compared perioperative complications among older and younger patients. Design Present study is based on retrospective outcomes comparison. Setting The study was conducted at a single neurosurgery institute at a quaternary center. Participants All older (age ≥ 65 years) and younger (<65 years) adult patients treated with World Health Organization grade 1 skull base meningiomas (2008-2017). Main Outcome Measures Perioperative complications and patient functional status are the primary outcomes of this study. Results The analysis included 287 patients, 102 older and 185 younger, with a mean (standard deviation [SD]) age of 72 (5) years and 51 (9) years ( p < 0.01). Older patients were more likely to have hypertension ( p < 0.01) and type 2 diabetes mellitus ( p = 0.01) but other patient and tumor factors did not differ ( p ≥ 0.14). Postoperative medical complications were not significantly different in older versus younger patients (10.8 [11/102] vs. 4.3% [8/185]; p = 0.06) nor were postoperative surgical complications (13.7 [14/102] vs. 10.8% [20/185]; p = 0.46). Following anterior skull base meningioma resection, diabetes insipidus (DI) was more common in older versus younger patients (14 [5/37] vs. 2% [1/64]; p = 0.01). Among older patients, a decreasing preoperative Karnofsky performance status score independently predicted perioperative complications by logistic regression analysis ( p = 0.02). Permanent neurologic deficits were not significantly different in older versus younger patients (12.7 [13/102] vs. 10.3% [19/185]; p = 0.52). Conclusion The overall perioperative complication profile of older and younger patients was similar after skull base meningioma resection. Older patients were more likely to experience DI after anterior skull base meningioma resection. Decreasing functional status in older patients predicted perioperative complications.

Residual Tumor Volume and Tumor Progression after Subtotal Resection and Observation of WHO Grade I Skull Base Meningiomas.

Objective This study investigated the impact of residual tumor volume (RTV) on tumor progression after subtotal resection and observation of WHO grade I skull base meningiomas. Study Design This study is a retrospective volumetric analysis. Setting This study was conducted at a single institution. Participants Patients who underwent subtotal resection of a WHO grade I skull base meningioma and postsurgical observation (July 1, 2007-July 1, 2017). Main Outcome Measure The main outcome was radiographic tumor progression. Results Sixty patients with residual skull base meningiomas were analyzed. The median (interquartile range) RTV was 1.3 (5.3) cm 3 . Tumor progression occurred in 23 patients (38.3%) at a mean duration of 28.6 months postsurgery. The 1-, 3-, and 5-year actuarial progression-free survival (PFS) rates were 98.3, 58.6, and 48.7%, respectively. The Cox multivariate analysis identified increasing RTV ( p = 0.01) and history of more than 1 previous surgery ( p = 0.03) as independent predictors of tumor progression. In a Kaplan-Meier analysis for PFS, the RTV threshold of 3 cm 3 maximized log-rank testing significance between groups of patients dichotomized at 0.5 cm 3 thresholds ( p < 0.01). The 3-year actuarial PFS rates for meningiomas with RTV ≤3 cm 3 and >3 cm 3 were 76.2 and 32.1%, respectively. When RTV >3 cm 3 was entered as a covariate in the Cox model, it was the only factor independently associated with tumor progression ( p < 0.01). Conclusion RTV was associated with tumor progression after subtotal resection of WHO grade I skull base meningioma in this cohort. An RTV threshold of 3 cm 3 was identified that minimized progression of the residual tumor when gross total resection was not safe or feasible.

Single-position prone lateral transpsoas approach: early experience and outcomes.

OBJECTIVE: Lateral lumbar interbody fusion (LLIF) via a transpsoas approach is a workhorse minimally invasive approach for lumbar arthrodesis that is often combined with posterior pedicle screw fixation. There has been increasing interest in performing single-position surgery, allowing access to the anterolateral and posterior spine without requiring patient repositioning. The feasibility of the transpsoas approach in patients in the prone position has been reported. Herein, the authors present a consecutive case series of all patients who underwent single-position prone transpsoas LLIF performed by an individual surgeon since adopting this approach. METHODS: A retrospective review was performed of a consecutive case series of adult patients (≥ 18 years old) who underwent single-position prone LLIF for any indication between October 2019 and November 2020. Pertinent operative details (levels, cage use, surgery duration, estimated blood loss, complications) and 3-month clinical outcomes were recorded. Intraoperative and 3-month postoperative radiographs were reviewed to assess for interbody subsidence. RESULTS: Twenty-eight of 29 patients (97%) underwent successful treatment with the prone lateral approach over the study interval; the approach was aborted in 1 patient, whose data were excluded. The mean (SD) age of patients was 67.9 (9.3) years; 75% (21) were women. Thirty-nine levels were treated: 18 patients (64%) had single-level fusion, 9 (32%) had 2-level fusion, and 1 (4%) had 3-level fusion. The most commonly treated levels were L3-4 (n = 15), L2-3 (n = 12), and L4-5 (n = 11). L1-2 was fused in 1 patient. The mean operative time was 286.5 (100.6) minutes, and the mean retractor time was 29.2 (13.5) minutes per level. The mean fluoroscopy duration was 215.5 (99.6) seconds, and the mean intraoperative radiation dose was 170.1 (94.8) mGy. Intraoperative subsidence was noted in 1 patient (4% of patients, 3% of levels). Intraoperative lateral access complications occurred in 11% of patients (1 cage repositioning, 2 inadvertent ruptures of anterior longitudinal ligament). Subsidence occurred in 5 of 22 patients (23%) with radiographic follow-up, affecting 6 of 33 levels (18%). Postoperative functional testing (Oswestry Disability Index, SF-36, visual analog scale-back and leg pain) identified significant improvement. CONCLUSIONS: This single-surgeon consecutive case series demonstrates that this novel technique is well tolerated and has acceptable clinical and radiographic outcomes. Larger patient series with longer follow-up are needed to further elucidate the safety profile and long-term outcomes of single-position prone LLIF.

Supine Lateral Lumbar Interbody Fusion: Cadaveric Proof of Principle for Simultaneous Anterior and Lateral Approaches.

BACKGROUND: Anterior lumbar interbody fusion (ALIF) and lateral lumbar interbody fusion (LLIF) are commonly performed in separate stages with a change in patient positioning to provide arthrodesis in the lumbar spine. Interest has emerged in performing these approaches as a single-stage surgery with the patient in the lateral decubitus position. The objective of this study was to evaluate the technical feasibility of performing minimally invasive anterolateral fixation in a single supine position. METHODS: Two fresh-frozen cadavers were used and placed supine. Standard minimally invasive anterior access was obtained by the approach surgeon. ALIF was performed at L5-S1 using standard techniques. A lateral incision was marked over the L4-5 disc space using fluoroscopy. Direct palpation and bimanual dissection were achieved through the same anterior incision, allowing access to the retroperitoneal space. Dilator and retractor docking was performed under fluoroscopic guidance. Direct visualization of the docking hardware through the anterior incision was used to ensure the safety of peritoneal contents and vasculature. LLIF was then performed using standard techniques at L4-5. RESULTS: Plain radiographs confirmed acceptable positioning of both ALIF and LLIF grafts. No injury to the cadaveric peritoneum, vasculature, or lumbar plexus was observed. A slightly enlarged anterior incision also permitted retroperitoneal access and visualization of the L3-4 disc space. CONCLUSIONS: This cadaveric feasibility study demonstrates that combined minimally invasive ALIF and LLIF may be performed as a single-stage procedure with the patient in the supine position. Clinical consideration and study of this approach are warranted.

Posterior Fossa Hemorrhage Following the Use of Low-Molecular-Weight Heparin: Lessons Learned and Recommendations for the Treatment and Prophylaxis of Postoperative Venous Thromboembolism.

Introduction Venous thromboembolism (VTE) is the most common preventable cause of morbidity and mortality among neurosurgery patients. Several studies have concluded that the use of chemical prophylaxis among patients undergoing a craniotomy reduces the incidence of VTE, and it is presumed to be safe. However, these studies do not differentiate between a supratentorial and posterior fossa craniotomy. Furthermore, the prophylactic or therapeutic use of low-molecular-weight heparin (LMWH) has been reported to increase the risk of intracranial hemorrhage. In this study, we describe the clinical details and outcomes for all patients who underwent posterior fossa craniotomy and developed posterior fossa hemorrhage secondary to postoperative use of LMWH during the study period. We also propose recommendations pertaining to postoperative heparin use after posterior fossa surgeries. Methods Data were retrospectively collected for patients presenting with posterior fossa hemorrhage following anticoagulant use among those who previously underwent posterior fossa craniotomy by the senior author (R.W.P.) from January 1, 2011, through December 31, 2018. Results We identified five patients who experienced postoperative hemorrhage while receiving LMWH in the initial setting of posterior fossa craniotomy. After hemorrhaging, four patients had low Glasgow Outcome Scale (GOS) scores (≤3) and failed to return to their baseline neurological status. These four patients had a Glasgow Coma Scale (GCS) score of 15/15 in the immediate postoperative period and received heparin within 72 hours of surgery. Conclusions Based on our findings, there is a possible association between the increased risk of hemorrhage and the early postoperative use of LMWH. The debilitating outcomes among the majority of these patients warrant the cautious use and further investigation of postoperative LMWH to appropriately quantify the risk. Further comparative studies with a larger sample size are required to provide insight into the pathophysiology of our findings.

Comparison of Surgical Outcomes and Recurrence Rates of Cystic and Solid Vestibular Schwannomas.

Objective Cystic vestibular schwannomas (CVSs) are anecdotally believed to have worse clinical and tumor-control outcomes than solid vestibular schwannomas (SVSs); however, no data have been reported to support this belief. In this study, we characterize the clinical outcomes of patients with CVSs versus those with SVSs. Design This is a retrospective review of prospectively collected data. Setting This study is set at single high-volume neurosurgical institute. Participants We queried a database for details on all patients diagnosed with vestibular schwannomas between January 2009 and January 2014. Main Outcome Measures Records were retrospectively reviewed and analyzed using univariate and multivariate analyses to study the differences in clinical outcomes and tumor progression or recurrence. Results Of a total of 112 tumors, 24% ( n = 27) were CVSs and 76% ( n = 85) were SVSs. Univariate analysis identified the extent of resection, Koos grade, and tumor diameter as significant predictors of recurrence ( p ≤ 0.005). However, tumor diameter was the only significant predictor of recurrence in the multivariate analysis ( p = 0.007). Cystic change was not a predictor of recurrence in the univariate or multivariate analysis ( p ≥ 0.40). Postoperative facial nerve and hearing outcomes were similar for both CVSs and SVSs ( p ≥ 0.47). Conclusion Postoperative facial nerve outcome, hearing, tumor progression, and recurrence are similar for patients with CVSs and SVSs. As CVS growth patterns and responses to radiation are unpredictable, we favor microsurgical resection over radiosurgery as the initial treatment. Our data do not support the commonly held belief that cystic tumors behave more aggressively than solid tumors or are associated with increased postoperative facial nerve deficits.

Prone Single-Position Lateral Lumbar Interbody Fusion With Posterior Decompression and Pedicle Screw Fixation for the Treatment of Grade II Spondylolisthesis: 2-Dimensional Operative Video.

Lateral lumbar interbody fusion (LLIF) provides indirect decompression without disruption of the posterior elements. It involves a larger implant footprint than that of posterior approaches. LLIF is typically performed with the patient in the lateral decubitus position. When a posterior fixation is indicated, a second-stage procedure is performed with the patient in the prone position. Single-position surgery provides the potential advantage of decreased operative time because both procedures can be performed without patient repositioning. Single-position LLIF and posterior fixation in the prone position have not been well validated to date. Herein, techniques for LLIF, percutaneous pedicle screw fixation, and facetectomy in the prone position are shown. A 76-yr-old woman with osteoporosis presented with severe back and bilateral leg pain refractory to conservative management and imaging findings of grade 2 dynamic anterolisthesis at L4-L5 with severe stenosis. She underwent LLIF with percutaneous pedicle screw fixation and facetectomy. She was placed on a Jackson table in the prone position for the entire procedure, which was performed in a single stage. Percutaneous pedicle screws were placed, followed by a left-sided minimally invasive facetectomy. A left-sided retroperitoneal transpsoas approach was used to perform the LLIF in standard fashion. Finally, the rods were locked into place. Postoperatively, the patient was neurologically stable, and imaging confirmed good hardware placement. At the 6-wk follow-up, the patient was doing well. This case demonstrates the feasibility of performing LLIF and posterior fixation in a single stage in the prone position. The patient provided informed consent. Used with permission from Barrow Neurological Institute.

Robotics in Spine Surgery: A Technical Overview and Review of Key Concepts.

The use of robotic systems to aid in surgical procedures has greatly increased over the past decade. Fields such as general surgery, urology, and gynecology have widely adopted robotic surgery as part of everyday practice. The use of robotic systems in the field of spine surgery has recently begun to be explored. Surgical procedures involving the spine often require fixation via pedicle screw placement, which is a task that may be augmented by the use of robotic technology. There is little margin for error with pedicle screw placement, because screw malposition may lead to serious complications, such as neurologic or vascular injury. Robotic systems must provide a degree of accuracy comparable to that of already-established methods of screw placement, including free-hand, fluoroscopically assisted, and computed tomography-assisted screw placement. In the past several years, reports have cataloged early results that show the robotic systems are associated with equivalent accuracy and decreased radiation exposure compared with other methods of screw placement. However, the literature is still lacking with regard to long-term outcomes with these systems. This report provides a technical overview of robotics in spine surgery based on experience at a single institution using the ExcelsiusGPS (Globus Medical; Audobon, PA, USA) robotic system for pedicle screw fixation. The current state of the field with regard to salient issues in robotics and future directions for robotics in spinal surgery are also discussed.

Pedicled, vascularized occipital bone graft to supplement atlantoaxial arthrodesis for the treatment of pseudoarthrosis.

Atlantoaxial pseudoarthrosis is a challenging postoperative complication. The use of a local, vascularized bone graft, without free tissue transfer, to support a revision atlantoaxial fusion has not been previously described. We report the first surgical patient who received a semispinalis capitis muscle pedicled, occipital bone graft for supplementation of a revision atlantoaxial arthrodesis. A 72-year-old female had a failed atlantoaxial fusion and developed neck pain from continued instability and fractured hardware. The fixation and fusion were revised and supplemented with a novel, pedicled occipital bone graft. A craniectomy was performed in the occipital bone while still attached to the semispinalis capitis muscle to provide graft vascularity. This graft was rotated inferiorly from the skull base to the C1 arch and C2 spinous process in order to supplement a revision atlantoaxial arthrodesis. The patient had excellent clinical recovery over 18-month clinical follow up. The bone graft harvesting and rotation were performed safely and without complication. The 6-month postoperative CT scan showed partial fusion into the graft. This novel surgical technique leverages the advantages of vascularized structural autograft without adding extensive time or morbidity to the procedure as observed in free-tissue transfers. It is a safe and useful salvage technique to supplement revision atlantoaxial fusion surgeries.

A Quantitative Assessment of the Accuracy and Reliability of Robotically Guided Percutaneous Pedicle Screw Placement: Technique and Application Accuracy.

BACKGROUND: Minimally invasive surgery (MIS) and anterior (ALIF), transforaminal (TLIF), or lateral lumbar interbody fusion (LLIF) often require percutaneous pedicle screw fixation (PSF) to achieve circumferential fusion. Robotic guidance technology may augment workflow to improve screw placement and decrease operative time. OBJECTIVE: To report surgical experience with robotically assisted percutaneous screw placement following LLIF. METHODS: Data from fusions with robotically assisted PSF in prone or lateral decubitus positions was reviewed. A CT-guided robotic guidance arm was used for screw placement (Excelsius GPS™, Globus Medical Inc, Audubon, Pennsylvania). Postoperative CT imaging facilitated screw localization. 3-dimensional and 2-dimensional coordinates of the screw tip and tail were calculated and compared with a target trajectory to calculate targeting errors. Breach was defined as a violation of the lateral or medial pedicle wall. RESULTS: Robotic-guided screw placement was successful in 28/31 patients. In those patients, 116/116 screws were successfully implanted. The breach rate was 3.4% (4/116). Across 17 patients (70 screws), mean 3-D accuracy was 5.0 ± 2.4 mm, mean 2-D accuracy was 2.6 ± 1.1 mm, and mean angular offset was 5.6 ± 4.3° with corresponding intraclass correlation coefficients (ICC) of 0.775 and 0.693. 3-dimensional accuracy correlated with age (R = 0.306, P = .011) and BMI (R = 0.252, P = .038). Accuracy did not significantly differ among vertebral body levels (P > .22). Mean operative time for MIS-TLIF and percutaneous screws was 277 ± 52 and 183 ± 54 min, respectively. Operative time did not significantly decrease across either group (P > .187). CONCLUSION: The Excelsius GPS™ robotic guidance system allows accurate PSF in most cases with 2 mm 2-D accuracy. Future studies are needed to demonstrate the utility of this novel guidance system and workflow improvement.

CyberKnife radiosurgery for acoustic neuromas: Tumor control and clinical outcomes.

Fractionated CyberKnife radiosurgery (CKRS) treatment for acoustic neuromas may reduce the risk of long-term radiation toxicity to nearby critical structures compared to that of single-fraction radiosurgery. However, tumor control rates and clinical outcomes after CKRS for acoustic neuromas are not well described. We retrospectively reviewed all acoustic neuroma patients treated with CKRS (2004-2011) in a prospectively maintained clinical and radiographic database. Treatment failure, the need for additional surgical intervention, was evaluated using Kaplan-Meier analysis. For 119 treated patients, median values were 49 months (range, 6-133 months) of follow-up, 1.6 cm3 (range, 0.02-17 cm3) tumor volume, and 18 Gy (range, 13-25 Gy) prescribed dose delivered in 3 fractions (range, 1-5 fractions). Thirty-five of 59 patients (59%) with pre-radiosurgery serviceable hearing (American Academy of Otolaryngology-Head and Neck Surgery class A or B) maintained serviceable hearing at the last audio follow-up (median, 21 months). Two of 111 patients (2%) with facial nerve function House-Brackmann (HB) grade ≤3 progressed to HB grade >3 after radiosurgery. Koos grade IV was predictive of radiographic tumor growth after radiosurgery compared to grades I to III (p = 0.02). Treatment failure occurred in 9 of 119 patients (8%); median time to failure was 29 months (range, 4-70 months). The actuarial rates of tumor control at 1, 3, 5, and 7 years were 96%, 94%, 88%, and 88%, respectively. CKRS affords effective tumor control for acoustic neuromas with an acceptable rate of hearing preservation. Further studies are needed to compare CKRS to single-fraction radiosurgery for acoustic neuromas.

Barrow Innovation Center Case Series: Early Clinical Experience with Novel Surgical Instrument Used To Prevent Intraoperative Spinal Cord Injuries.

OBJECTIVE: The Barrow Innovation Center comprises an educational program in medical innovation that enables residents to identify problems in patient care and rapidly develop and implement solutions to these problems. Residents involved in this program noted an elevated risk of iatrogenic spinal cord injury during posterior cervical and thoracic procedures. The objective of this study was to describe this complication, and a novel solution was developed through a new innovation training program. METHODS: A case report demonstrates the risk of iatrogenic spinal cord injury during posterior cervical decompression and fusion. Solutions to this problem were developed at the innovation center via an iterative process of prototype creation, cadaveric testing, and redesign. Patent law students who partnered with the center wrote and filed a provisional patent protecting the novel prototype designs. RESULTS: The concept of a protective shield for the spinal cord was developed, and within only 6 weeks the devices were provisionally patented and used in the operating room. This device was named the Myeloshield. Initial clinical experience indicates that the Myeloshield can be used without impeding the flow of surgery and has the potential to prevent iatrogenic spinal cord injury; this experience is presented through 2 case reports demonstrating the use of Myeloshields in the operating room. CONCLUSIONS: This report demonstrates how programs like the Barrow Innovation Center can provide neurosurgery residents with a unique educational experience in medical device innovation and intellectual property development and can serve as an avenue of surgical quality improvement and problem solving.

Long-Term Facial Nerve Outcomes after Microsurgical Resection of Vestibular Schwannomas in Patients with Preoperative Facial Nerve Palsy.

Objectives This study aimed at evaluating facial nerve outcomes in vestibular schwannoma patients presenting with preoperative facial nerve palsy. Design A retrospective review. Setting Single-institution cohort. Participants Overall, 368 consecutive patients underwent vestibular schwannoma resection. Patients with prior microsurgery or radiosurgery were excluded. Main Outcome Measures Incidence, House-Brackmann grade. Results Of 368 patients, 9 had confirmed preoperative facial nerve dysfunction not caused by prior treatment, for an estimated incidence of 2.4%. Seven of these nine patients had Koos grade 4 tumors. Mean tumor diameter was 3.0 cm (range: 2.1-4.4 cm), and seven of nine tumors were subtotally resected. All nine patients were followed up clinically for ≥ 6 months. Of the six patients with a preoperative House-Brackmann grade of II, two improved to grade I, three were stable, and one patient worsened to grade III. Of the three patients with grade III or worse, all remained stable at last follow-up. Conclusions Preoperative facial nerve palsy is rare in patients with vestibular schwannoma; it tends to occur in patients with relatively large lesions. Detailed long-term outcomes of facial nerve function after microsurgical resection for these patients have not been reported previously. We followed nine patients and found that eight (89%) of the nine patients had either stable or improved facial nerve outcomes after treatment. Management strategies varied for these patients, including rates of subtotal versus gross-total resection and the use of stereotactic radiosurgery in patients with residual tumor. These results can be used to help counsel patients preoperatively on expected outcomes of facial nerve function after treatment.