Single-position prone transpsoas fusion for the treatment of lumbar adjacent segment disease: early experience of twenty-four cases across three tertiary medical centers.

PURPOSE: Prone transpsoas fusion (PTP) is a minimally invasive technique that maximizes the benefit of lateral access interbody surgery and the prone positioning for surgically significant adjacent segment disease. The authors describe the feasibility, reproducibility and radiographic efficacy of PTP when performed for cases of lumbar ASD. METHODS: Adult patients undergoing PTP for treatment of lumbar ASD at three institutions were retrospectively enrolled. Demographic information was recorded, as was operative data such as adjacent segment levels, operative time, blood loss, laterality of approach, open versus percutaneous pedicle screw instrumentation and need for primary decompression. Radiographic measurements including segmental and global lumbar lordosis, pelvic incidence, pelvic tilt, sacral slope and sagittal vertical axis were recorded both pre- and immediately post-operatively. RESULTS: Twenty-four patients met criteria for inclusion. Average age was 60.4 ± 10.4 years and average BMI was 31.6 ± 5.0 kg/m2. Total operative time was 204.7 ± 83.3 min with blood loss of 187.9 ± 211 mL. Twenty-one patients had pedicle screw instrumentation exchanged percutaneously and 3 patients had open pedicle screw exchange. Two patients suffered pulmonary embolism that was treated medically with no long-term sequelae. One patient had transient lumbar radicular pain and all patients were discharged home with an average length of stay of 3.0 days (range 1-6). Radiographically, global lumbar lordosis improved by an average of 10.3 ± 9.0 degrees, segmental lordosis by 10.1 ± 13.3 degrees and sagittal vertical axis by 3.2 ± 3.2 cm. CONCLUSION: Single-position prone transpsoas lumbar interbody fusion is a clinically reproducible minimally invasive technique that can effectively treat lumbar adjacent segment disease.

Successful Neonatal, Intraoperative Neuromonitoring in the Surgical Correction of a Thoracic Dermal Sinus Tract: Technical Note.

INTRODUCTION: Intraoperative neuromonitoring (IONM) is commonly used during surgery of the spine and spinal cord for early surveillance of iatrogenic injury to the central and peripheral nervous system. However, for infants and young children under 3 years of age, the use of IONM is challenging due to incomplete central and peripheral myelination. CASE PRESENTATION: We report a case of a T4-T6 dermal sinus tract (DST) that was resected on day of life 23, with the successful use of IONM. CONCLUSION: To our knowledge, this is the youngest reported case of the use of IONM in the surgical correction of a DST in a neonatal patient. This case demonstrates the potential efficacy of IONM in neonatal spine surgery and the techniques used to adapt the technology to an immature nervous system.

Immune suppression in gliomas.

INTRODUCTION: The overall survival in patients with gliomas has not significantly increased in the modern era, despite advances such as immunotherapy. This is in part due to their notorious ability to suppress local and systemic immune responses, severely restricting treatment efficacy. METHODS: We have reviewed the preclinical and clinical evidence for immunosuppression seen throughout the disease process in gliomas. This review aims to discuss the various ways that brain tumors, and gliomas in particular, co-opt the body's immune system to evade detection and ensure tumor survival and proliferation. RESULTS: A multitude of mechanisms are discussed by which neoplastic cells evade detection and destruction by the immune system. These include tumor-induced T-cell and NK cell dysfunction, regulatory T-cell and myeloid-derived suppressor cell expansion, M2 phenotypic transformation in glioma-associated macrophages/microglia, upregulation of immunosuppressive glioma cell surface factors and cytokines, tumor microenvironment hypoxia, and iatrogenic sequelae of immunosuppressive treatments. CONCLUSIONS: Gliomas create a profoundly immunosuppressive environment, both locally within the tumor and systemically. Future research should aim to address these immunosuppressive mechanisms in the effort to generate treatment options with meaningful survival benefits for this patient population.

Management of unruptured incidentally found intracranial saccular aneurysms.

Unruptured intracranial saccular aneurysms occur in 3-5% of the general population. As the use of diagnostic medical imaging has steadily increased over the past few decades with the increased availability of computed tomography (CT) and magnetic resonance imaging (MRI), so has the detection of incidental aneurysms. The management of an unruptured intracranial saccular aneurysm is challenging for both patients and physicians, as the decision to intervene must weigh the risk of rupture and resultant subarachnoid hemorrhage against the risk inherent to the surgical or endovascular procedure. The purpose of this paper is to provide an overview of factors to be considered in the decision to offer treatment for unruptured intracranial aneurysms in adults. In addition, we review aneurysm and patient characteristics that favor surgical clipping over endovascular intervention and vice versa. Finally, the authors propose a novel, simple, and clinically relevant algorithm for observation versus intervention in unruptured intracranial aneurysms based on the PHASES scoring system.

The intersection between immunotherapy and laser interstitial thermal therapy: a multipronged future of neuro-oncology.

The rise of immunotherapy (IT) in oncological treatment has greatly improved outcomes in a number of disease states. However, its use in tumors of the central nervous system (CNS) remains limited for multiple reasons related to the unique immunologic tumor microenvironment. As such, it is valuable to consider the intersection of IT with additional treatment methods that may improve access to the CNS and effectiveness of existing IT modalities. One such combination is the pairing of IT with localized hyperthermia (HT) generated through technologies such as laser interstitial thermal therapy (LITT). The wide-ranging immunomodulatory effects of localized and whole-body HT have been investigated for some time. Hyperthermia has demonstrated immunostimulatory effects at the level of tumor cells, immune cells, and the broader environment governing potential immune surveillance. A thorough understanding of these effects as well as the current and upcoming investigations of such in combination with IT is important in considering the future directions of neuro-oncology.

Management of Postoperative Pain after Elective Craniotomy: A Prospective Randomized Controlled Trial of a Neurosurgical Enhanced Recovery after Surgery (ERAS) Program.

Objective: To prospectively evaluate the efficacy of a neurosurgical enhanced recovery after surgery (ERAS) protocol on the management of postoperative pain after elective craniotomies. Methods: This randomized controlled trial was conducted in the neurosurgical center of Tangdu Hospital (Fourth Military Medical University, Xi'an, China). A total of 129 patients undergoing craniotomies between October 2016 and July 2017 were enrolled in a randomized clinical trial comparing an ERAS protocol to a conventional postoperative care regimen. The primary outcome was the postoperative pain score assessed by a verbal numerical rating scale (NRS). Results: Patients in the ERAS group had a significant reduction in their postoperative pain scores on POD 1 compared to patients in the control group (p < 0.05). More patients (n = 44, 68.8%) in the ERAS group experienced mild pain (NRS: 1 to 3) on POD1 compared with patients (n = 23, 35.4%) in the control group (p < 0.05). A further reduction in pain scores was also observed on POD 2 and maintained on POD 3 in the ERAS group compared with that in the control group. In addition, the median postoperative length of hospital stay was significantly decreased with the incorporation of the ERAS protocol compared to controls (ERAS: 4 days, control: 7 days, P<0.001). Conclusion: The implementation of a neurosurgical ERAS protocol for elective craniotomy patients has significant benefits in alleviating postoperative pain and enhancing recovery leading to early discharge after surgery compared to conventional care. Further evaluation of this protocol in larger, multi-center studies is warranted.

The medicolegal impact of misplaced pedicle and lateral mass screws on spine surgery in the United States.

Spine surgery has been disproportionately impacted by medical liability and malpractice litigation, with the majority of claims and payouts related to procedural error. One common area for the potential avoidance of malpractice claims and subsequent payouts involves misplaced pedicle and/or lateral mass instrumentation. However, the medicolegal impact of misplaced screws on spine surgery has not been directly reported in the literature. The authors of the current study aimed to describe this impact in the United States, as well as to suggest a potential method for mitigating the problem.This retrospective analysis of 68 closed medicolegal cases related to misplaced screws in spine surgery showed that neurosurgeons and orthopedic spine surgeons were equally named as the defendant (n = 32 and 31, respectively), and cases were most commonly due to misplaced lumbar pedicle screws (n = 41, 60.3%). Litigation resulted in average payouts of $1,204,422 ± $753,832 between 1995 and 2019, when adjusted for inflation. The median time to case closure was 56.3 (35.2-67.2) months when ruled in favor of the plaintiff (i.e., patient) compared to 61.5 (51.4-77.2) months for defendant (surgeon) verdicts (p = 0.117).

Tonsillectomy with modified reconstruction of the cisterna magna with and without craniectomy for the treatment of adult Chiari malformation type I with syringomyelia.

BACKGROUND: In light of the controversies regarding the surgical treatment of adult Chiari malformation type I (CM-I) with syringomyelia, a retrospective study was conducted to evaluate the safety and efficacy of tonsillectomy followed by modified reconstruction of the cisterna magna with or without craniectomy. METHODS: Between 2008 and 2017, 78 adult CM-I patients (36 males and 42 females, mean age 40.6 years old) with syringomyelia were treated with posterior fossa decompression (PFD) with tonsillectomy and modified reconstruction of the cisterna magna. Patients were divided into two study groups: group A (n = 40) underwent cranioplasty with replacement of the bone flap; group B (n = 38) underwent suboccipital craniectomy. Neurological outcomes were evaluated by traditional physician assessment (improved, unchanged, and worsened) and the Chicago Chiari Outcome Scale (CCOS). Syringomyelia outcomes were assessed radiologically. RESULTS: The procedure was successfully performed in all patients, and restoration of normal cerebrospinal fluid (CSF) flow was confirmed by intraoperative ultrasonography. The median postoperative follow-up was 20.3 months (range 18-60 months). Clinical improvement was evident in 66 (84.6%) patients, with no significant differences between the two groups (85.0% vs. 84.2%, P = 0.897). According to the CCOS, 36 patients (90.0%) in group A were labeled as "good" outcome, compared with that of 34 (86.8%) in group B (P = 0.734). Improvement of syringomyelia was also comparable between the groups, which was observed in 35 (87.5%) vs. 33 (86.8%) patients (P = 0.887). The postoperative overall (7.5% vs. 23.7%, P = 0.048) and CSF-related (2.5% vs. 18.4%, P = 0.027) complication rates were significantly lower in group A than group B. CONCLUSIONS: Tonsillectomy with modified reconstruction of the cisterna magna without craniectomy seems to be a safe and effective surgical option to treat adult CM-I patients with syringomyelia, though future well-powered prospective randomized studies are warranted to validate these findings.

Computer-Assisted Instrument Navigation Versus Conventional C-Arm Fluoroscopy for Surgical Instrumentation: Accuracy, Radiation Time, and Radiation Exposure.

OBJECTIVE. Compared with open procedures, minimally invasive surgical procedures are associated with increased radiation exposure and long-term health risks. Ultralow radiation imaging coupled with image enhancement and instrument tracking (ULRI-IE/IT) is a new image modifier that allows a computer to show real-time movement of an instrument as it is adjusted, mimicking live fluoroscopy but without continuous radiation production. The purpose of this study was to determine the accuracy and radiation output of ULRI-IE/IT compared with unassisted conventional fluoroscopy in a variety of surgical procedures. MATERIALS AND METHODS. Physicians of various specialties were asked to identify the ideal location for instrumentation in various spinal, orthopedic, pain, and physiatric procedures and then place an instrument in this location in a cadaver both with and without ULRI-IE/IT assistance. Whether ULRI-IE/IT was used was randomly assigned to reduce the impact of learning. Radiation exposure, time to place the instrument, and the number of images required to achieve accurate positioning were recorded for each procedure. These were compared for unassisted and ULRI-IE/IT-assisted fluoroscopy to determine the utility of ULRI-IE/IT in minimally invasive instrumentation. RESULTS. Twenty-three trials of nine procedures by five physicians were completed both with and without assistance of ULRI-IE/IT. The procedures ranged from percutaneous pedicle screw insertion to foramen ovale ablation. Total time to localize the instrument for all 23 cases was 31.2% longer without assistance. Use of ULRI-IE/IT reduced the total number of images per case by 74.8% and radiation exposure by 91.8%. With ULRI-IE/IT, physicians were able to successfully place the instrument in the correct location on the first attempt in 82.6% of trials and in the second attempt in all trials versus a mean of 4.65 images needed for unassisted fluoroscopy. CONCLUSION. Use of ULRI-IE/IT can dramatically reduce radiation output and the number of images acquired and time required to perform fluoroscopic procedures.

Developing Therapies for Brain Tumors: The Impact of the Johns Hopkins Hunterian Neurosurgical Research Laboratory.

The Johns Hopkins Hunterian Neurosurgical Laboratory at the Johns Hopkins University School of Medicine was created in 1904 by Harvey Cushing and William Halsted and has had a long history of fostering surgical training, encouraging basis science research, and facilitating translational application. Over the past 30 years, the laboratory has addressed the paucity of brain tumor therapies. Pre-clinical work from the laboratory led to the development of carmustine wafers with initial US Food and Drug Administration (FDA) approval in 1996. Combining carmustine wafers, radiation, and temozolomide led to a significant increase in the median survival of patients with glioblastoma. The laboratory has also developed microchips and immunotherapy to further extend survival in this heretofore underserved population. These achievements were made possible by the dedication, commitment, and creativity of more than 300 trainees of the Hunterian Neurosurgical Laboratory. The laboratory demonstrates the beneficial influence of research experience as well its substantial impact on the field of biomedical research.

The effect of regadenoson-induced transient disruption of the blood-brain barrier on temozolomide delivery to normal rat brain.

The blood-brain barrier (BBB) significantly reduces the delivery of many systemically administered agents to the central nervous system. Although temozolomide is the only chemotherapy to improve survival in patients with glioblastoma, its concentration in brain is only 20 % of that in blood. Regadenoson, an FDA approved adenosine receptor agonist used for cardiac stress testing, transiently disrupts rodent BBB allowing high molecular weight dextran (70 kD) to enter the brain. This study was conducted to determine if regadenoson could facilitate entry of temozolomide into normal rodent brain. Temozolomide (50 mg/kg) was administered by oral gavage to non-tumor bearing F344 rats. Two-thirds of the animals received a single dose of intravenous regadenoson 60-90 min later. All animals were sacrificed 120 or 360 min after temozolomide administration. Brain and plasma temozolomide concentrations were determined using HPLC/MS/MS. Brain temozolomide concentrations were significantly higher at 120 min when it was given with regadenoson versus alone (8.1 ± 2.7 and 5.1 ± 3.5 µg/g, P < 0.05). A similar trend was noted in brain:plasma ratios (0.45 ± 0.08 and 0.29 ± 0.09, P < 0.05). Brain concentrations and brain:plasma ratios were not significantly different 360 min after temozolomide administration. No differences were seen in plasma temozolomide concentrations with or without regadenoson. These results suggest co-administration of regadenoson with temozolomide results in 60% higher temozolomide levels in normal brain without affecting plasma concentrations. This novel approach to increasing intracranial concentrations of systemically administered agents has potential to improve the efficacy of chemotherapy in neuro-oncologic disorders.

Timing of surgical treatment for idiopathic normal pressure hydrocephalus: association between treatment delay and reduced short-term benefit.

OBJECTIVE A growing body of evidence suggests that longer durations of preoperative symptoms may correlate with worse postoperative outcomes following cerebrospinal fluid (CSF) diversion for treatment of idiopathic normal pressure hydrocephalus (iNPH). The aim of this study is to determine whether the duration of preoperative symptoms alters postoperative outcomes in patients treated for iNPH. METHODS The authors conducted a retrospective review of 393 cases of iNPH involving patients treated with ventriculoperitoneal (VP) shunting. The duration of symptoms prior to the operative intervention was recorded. The following outcome variables were assessed at baseline, 6 months postoperatively, and at last follow-up: gait performance, urinary continence, and cognition. RESULTS The patients' median age at shunt placement was 74 years. Increased symptom duration was significantly associated with worse gait outcomes (relative risk (RR) 1.055 per year of symptoms, p = 0.037), and an overall absence of improvement in any of the classic triad symptomology (RR 1.053 per year of symptoms, p = 0.033) at 6 months postoperatively. Additionally, there were trends toward significance for symptom duration increasing the risk of having no 6-month postoperative improvement in urinary incontinence (RR 1.049 per year of symptoms, p = 0.069) or cognitive symptoms (RR 1.051 per year of symptoms, p = 0.069). However, no statistically significant differences were noted in these outcomes at last follow-up (median 31 months). Age stratification by decade revealed that prolonging symptom duration was significantly associated with lower Mini-Mental Status Examination scores in patients aged 60-70 years, and lack of cognitive improvement in patients aged 70-80 years. CONCLUSIONS Patients with iNPH with longer duration of preoperative symptoms may not receive the same short-term benefits of surgical intervention as patients with shorter duration of preoperative symptoms. However, with longer follow-up, the patients generally reached the same end point. Therefore, when managing patients with iNPH, it may take longer to see the benefits of CSF shunting when patients present with a longer duration of preoperative symptoms.

Automated segmentation of ablated lesions using deep convolutional neural networks: A basis for response assessment following laser interstitial thermal therapy.

BACKGROUND: Laser interstitial thermal therapy (LITT) of intracranial tumors or radiation necrosis enables tissue diagnosis, cytoreduction, and rapid return to systemic therapies. Ablated tissue remains in situ, resulting in characteristic post-LITT edema associated with transient clinical worsening and complicating post-LITT response assessment. METHODS: All patients receiving LITT at a single center for tumors or radiation necrosis from 2015 to 2023 with ≥9 months of MRI follow-up were included. An nnU-Net segmentation model was trained to automatically segment contrast-enhancing lesion volume (CeLV) of LITT-treated lesions on T1-weighted images. Response assessment was performed using volumetric measurements. RESULTS: Three hundred and eighty four unique MRI exams of 61 LITT-treated lesions and 6 control cases of medically managed radiation necrosis were analyzed. Automated segmentation was accurate in 367/384 (95.6%) images. CeLV increased to a median of 68.3% (IQR 35.1-109.2%) from baseline at 1-3 months from LITT (P = 0.0012) and returned to baseline thereafter. Overall survival (OS) for LITT-treated patients was 39.1 (9.2-93.4) months. Lesion expansion above 40% from volumetric nadir or baseline was considered volumetric progression. Twenty-one of 56 (37.5%) patients experienced progression for a volumetric progression-free survival of 21.4 (6.0-93.4) months. Patients with volumetric progression had worse OS (17.3 vs 62.1 months, P = 0.0015). CONCLUSIONS: Post-LITT CeLV expansion is quantifiable and resolves within 6 months of LITT. Development of response assessment criteria for LITT-treated lesions is feasible and should be considered for clinical trials. Automated lesion segmentation could speed the adoption of volumetric response criteria in clinical practice.

A Comparison of Percutaneous Pedicle Screw Accuracy Between Robotic Navigation and Novel Fluoroscopy-Based Instrument Tracking for Patients Undergoing Instrumented Thoracolumbar Surgery.

BACKGROUND: The accuracy of pedicle screws placed with instrument tracking and robotic navigation are individually comparable or superior to placement using standard fluoroscopy, however head-to-head comparisons between these adjuncts in a similar surgical population have yet to be performed. METHODS: Consecutive patients undergoing percutaneous thoracic and lumbosacral spinal instrumentation were retrospectively enrolled. Instrumentation was performed using either fluoroscopy-based instrument tracking system (TrackX, TrackX Technologies) or robotic-navigation (ExcelsiusGPS, Globus Medical). Postinstrumentation computed tomography scans were graded for breach according to the Gertzbein-Robbins scale, with "acceptable" screws deemed as Grade A or B and "unacceptable" screws deemed as Grades C through E. Accuracy data was compared between both instrumentation modalities. RESULTS: Fifty-three patients, comprising a total of 250 screws (167 robot, 83 instrument tracking) were included. The overall accuracy between both modalities was similar, with 96.4% and 97.6% of screws with acceptable accuracy between instrument tracking and robotic navigation, respectively (I-squared 0.30, df = 1, P = 0.58). Between instrument tracking and robotic navigation, 92.8% and 95.8% of screws received Grade A, 3.6% and 1.8% a Grade B, 1.2% and 1.2% a Grade C, 1.2% and 0.6% a Grade D, and 1.2% and 0.6% a Grade E, respectively. The robot was abandoned intraoperatively in 2 cases due to unrecoverable registration inaccuracy or software failure, leading to abandonment of 8 potential screws (4.8%). CONCLUSIONS: In a similar patient population, there is a similarly high degree of instrumentation accuracy between fluoroscopy-based instrument tracking and robotic navigation. There is a rare chance for screw breach with either surgical adjunct.

Preoperative validation of edema-corrected tractography in neurosurgical practice: translating surgeon insights into novel software implementation.

Background: Peritumoral edema alters diffusion anisotropy, resulting in false negatives in tractography reconstructions negatively impacting surgical decision-making. With supratotal resections tied to survival benefit in glioma patients, advanced diffusion modeling is critical to visualize fibers within the peritumoral zone to prevent eloquent fiber transection thereafter. A preoperative assessment paradigm is therefore warranted to systematically evaluate multi-subject tractograms along clinically meaningful parameters. We propose a novel noninvasive surgically-focused survey to evaluate the benefits of a tractography algorithm for preoperative planning, subsequently applied to Synaptive Medical's free-water correction algorithm developed for clinically feasible single-shell DTI data. Methods: Ten neurosurgeons participated in the study and were presented with patient datasets containing histological lesions of varying degrees of edema. They were asked to compare standard (uncorrected) tractography reconstructions overlaid onto anatomical images with enhanced (corrected) reconstructions. The raters assessed the datasets in terms of overall data quality, tract alteration patterns, and the impact of the correction on lesion definition, brain-tumor interface, and optimal surgical pathway. Inter-rater reliability coefficients were calculated, and statistical comparisons were made. Results: Standard tractography was perceived as problematic in areas proximal to the lesion, presenting with significant tract reduction that challenged assessment of the brain-tumor interface and of tract infiltration. With correction applied, significant reduction in false negatives were reported along with additional insight into tract infiltration. Significant positive correlations were shown between favorable responses to the correction algorithm and the lesion-to-edema ratio, such that the correction offered further clarification in increasingly edematous and malignant lesions. Lastly, the correction was perceived to introduce false tracts in CSF spaces and - to a lesser degree - the grey-white matter interface, highlighting the need for noise mitigation. As a result, the algorithm was modified by free-water-parameterizing the tractography dataset and introducing a novel adaptive thresholding tool for customizable correction guided by the surgeon's discretion. Conclusion: Here we translate surgeon insights into a clinically deployable software implementation capable of recovering peritumoral tracts in edematous zones while mitigating artifacts through the introduction of a novel and adaptive case-specific correction tool. Together, these advances maximize tractography's clinical potential to personalize surgical decisions when faced with complex pathologies.

Time to Steroid Independence After Laser Interstitial Thermal Therapy vs Medical Management for Treatment of Biopsy-Proven Radiation Necrosis Secondary to Stereotactic Radiosurgery for Brain Metastasis.

BACKGROUND: Radiation necrosis (RN) after stereotactic radiosurgery (SRS) for brain metastases (BM) can result in significant morbidity, compounded by the effects of extended steroid therapy. Laser interstitial thermal therapy (LITT) is a minimally invasive procedure that can offer definitive treatment for RN while potentially obviating the need for prolonged steroid use. OBJECTIVE: To compare LITT vs medical management (MM) in the treatment of RN. METHODS: A multicenter, retrospective study was performed of SRS-treated patients with BM who developed biopsy-proven RN and were treated with LITT or MM. Clinical outcome data were compared by treatment modality. RESULTS: Seventy-two patients met criteria with a median follow-up of 10.0 months (4.2-25.1), and 57 patients (79%) underwent LITT. Four MM (27%) and 3 LITT patients (5%) demonstrated radiographic progression (P = .031) at a median of 5.3 and 4.0 months (P = .40). There was no significant difference in overall survival (LITT median of 15.2 vs 11.6 months, P = .60) or freedom from local progression (13.6 vs 7.06 months, P = .40). Patients stopped steroid therapy earlier in the LITT cohort at a median of 37 days compared with 245 days (P < .001). When controlled for follow-up duration, patients treated with LITT were 3 times more likely to be weaned off steroids before the study end point (P = .003). CONCLUSION: These data suggest that LITT for treatment of biopsy-proven RN after SRS for BM significantly decreases time to steroid independence. Prospective trials should be designed to further validate the utility of LITT for RN and its impact on steroid-induced morbidity.

Combination laser interstitial thermal therapy plus stereotactic radiotherapy increases time to progression for biopsy-proven recurrent brain metastases.

Background: Improved survival for patients with brain metastases has been accompanied by a rise in tumor recurrence after stereotactic radiotherapy (SRT). Laser interstitial thermal therapy (LITT) has emerged as an effective treatment for SRT failures as an alternative to open resection or repeat SRT. We aimed to evaluate the efficacy of LITT followed by SRT (LITT+SRT) in recurrent brain metastases. Methods: A multicenter, retrospective study was performed of patients who underwent treatment for biopsy-proven brain metastasis recurrence after SRT at an academic medical center. Patients were stratified by "planned LITT+SRT" versus "LITT alone" versus "repeat SRT alone." Index lesion progression was determined by modified Response Assessment in Neuro-Oncology Brain Metastases (RANO-BM) criteria. Results: Fifty-five patients met inclusion criteria, with a median follow-up of 7.3 months (range: 1.0-30.5), age of 60 years (range: 37-86), Karnofsky Performance Status (KPS) of 80 (range: 60-100), and pre-LITT/biopsy contrast-enhancing volume of 5.7 cc (range: 0.7-19.4). Thirty-eight percent of patients underwent LITT+SRT, 45% LITT alone, and 16% SRT alone. Median time to index lesion progression (29.8, 7.5, and 3.7 months [P = .022]) was significantly improved with LITT+SRT. When controlling for age in a multivariate analysis, patients treated with LITT+SRT remained significantly less likely to have index lesion progression (P = .004). Conclusions: These data suggest that LITT+SRT is superior to LITT or repeat SRT alone for treatment of biopsy-proven brain metastasis recurrence after SRT failure. Prospective trials are warranted to validate the efficacy of using combination LITT+SRT for treatment of recurrent brain metastases.

The Impact of Instrumentation and Implant Surface Technology on Cervical and Thoracolumbar Fusion.

Spinal fusion has undergone significant evolution and improvement over the past 50 yr. Historically, spine fusion was noninstrumented and arthrodesis was based entirely on autograft. Improved understanding of spinal anatomy and materials science ushered in a new era of spinal fusion equipped with screw-based technologies and various interbody devices. Osteobiologics is another important realm of spine fusion, and the evolution of various osteobiologics has perhaps undergone the most change within the past 20 yr. A new element to spinal instrumentation has recently gained traction-namely, surface technology. New data suggest that surface treatments play an increasingly well-recognized role in inducing osteogenesis and successful fusion. Until now, however, there has yet to be a unified resource summarizing the existing data and a lack of consensus exists on superior technology. Here, authors provide an in-depth review on surface technology and its impact on spinal arthrodesis.

Operative time and learning curve between fluoroscopy-based instrument tracking and robot-assisted instrumentation for patients undergoing minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF).

INTRODUCTION: Instrument-navigation modalities including CT-guided and robot-assisted methods claim both efficacy and accuracy when applied to spine surgery, yet often increase setup and operating times which can translate to increased costs. To see the impact of different technologies on surgical efficiency, we studied the impact of a single surgeon's experience with a multitude of instrument navigational technologies. METHODS: Consecutive patients undergoing minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF) were analyzed. Consecutive cases were done with assistance of a robot (Mazor, Medtronic, Minneapolis, MN), with the assistance of fluoroscopic instrument-tracking (TrackX, North Carolina, USA), or fluoroscopy alone without adjunctive navigation in consecutive blocks of time. The cases done without assistance were used to normalize for number of interbody implants and decompressions performed as well as hardware removal if needed. Age, body mass index (BMI), sex, operative levels, laminectomy, need for hardware removal, and total operative time were recorded. RESULTS: A total of 119 cases (74 conventional, 13 robot-assisted, 32 instrument-tracking) were included in analysis. There were no significant differences in age, sex, or BMI between modalities. Average total operative time for robot-assisted, and instrument-tracking-assisted cases was 175.46 ± 46.86 min 119.63 ± 34.33 min, respectively, for each level (p < 0.05 across each group). After normalization against operative times from similar cases performed with conventional fluoroscopy, robotic-navigation added an average of 42.25 ± 28.35 min while use of instrument-tracking saved an average of 13.88 ± 38.69 min. There was no learning curve seen using robotic navigation, as operative times remained consistently longer than similar cases using conventional fluoroscopy and showed no sign of improvement over time. Cases using instrument-tracking were initially slower but trended downwards through approximately 11 patients, at which point operative times were consistently quicker (R2 = 0.39). None of the assisted cases were abandoned in favor of standard fluoroscopy or required hardware revision. CONCLUSION: Enabling technology can have a significant impact on surgical efficiency. Compared to MIS-TLIFs performed with standard fluoroscopy, those done with robotic-assistance consistently negatively impacted operative times while instrument-tracking was associated with a short learning curve and in the majority of cases studied showed improved operative times.

Percutaneous Lumbar Interbody Fusion With an Expandable Titanium Cage Through Kambin's Triangle: A Case Series With Initial Clinical and Radiographic Results.

BACKGROUND: There has been an increased interest in lumbar interbody fusions through Kambin's triangle. In this study, we describe percutaneous access to the lumbar disc and insertion of an expandable titanium cage through Kambin's triangle without facetectomy. The objective of this study is to determine the feasibility as well as clinical and radiographical outcomes of completely percutaneous lumbar interbody fusion (percLIF) using an expandable titanium cage through Kambin's triangle. METHODS: A retrospective review of patients undergoing single-level percLIF for grade 1 lumbar spondylolisthesis via Kambin's triangle using an expandable titanium cage was performed. Demographic information, Oswestry Disability Index (ODI), preoperative and postoperative radiographic factors, perioperative data, and complications were recorded. Fusion was assessed with 1-year postoperative computed tomography scan or lumbar spine x-ray and defined as bridging disc or posterolateral fusion without evidence of hardware fracture or perihardware lucency. RESULTS: A total of 16 patients (3 males) were included in this study. Spondylolisthesis, anterior disc height, and posterior disc height were significantly improved at 6 weeks, 6 months, and 12 months, postoperatively (P < 0.05). ODI was significantly improved by 24.4% at 12 months postoperatively (P = 0.0036). One patient was readmitted within 30 days for pain control but otherwise there were no complications including permanent neurological injury, infection, deep vein thrombosis, pulmonary embolism, or cardiac events. Fifteen (93.8%) patients had radiographic fusion at their 1-year postoperative imaging. CONCLUSION: Our initial experiences have shown that percLIF can be performed using an expandable titanium cage through Kambin's triangle with excellent radiographic and clinical results. In this series, percLIF is a safe and clinically efficacious procedure for reducing grade 1 lumbar spondylolisthesis and improving radiculopathy. This procedure is completed percutaneously without the use of an endoscope. CLINICAL RELEVANCE: This study highlights improvements in outcomes of minimally invasive surgery. LEVEL OF EVIDENCE: IV.