Minimally Invasive Spine Surgery Research Articles

Indications, Contraindications, and Complications of Biportal Endoscopic Decompressive Surgery for the Treatment of Lumbar Stenosis: A Systematic Review

Biportal endoscopic spine surgery is gaining popularity in managing degenerative lumbar diseases and has optimal indications and contraindications. The perioperative complications related to the biportal endoscopic approach affect the postoperative outcomes. Therefore, this study aimed to review the indications, contraindications, and complications of biportal endoscopic decompression for lumbar stenosis. For this systematic review, articles on biportal endoscopic decompressive surgery for lumbar stenosis, including central, lateral recess and foraminal stenoses, were searched for and reviewed. Additionally, the complications, indications, and contraindications of biportal endoscopic surgery for lumbar stenosis were reviewed. Forty-one articles were included in this study. The indications for biportal endoscopic decompression are central lumbar stenosis, central stenosis with lipomatosis, lateral recess stenosis, foraminal stenosis, and the far-out syndrome. The contraindications include trauma, infection, tumor, instability, high-grade spondylolisthesis, isthmic spondylolisthesis, and severe scoliosis. Perioperative complications are typically minor; major complications include durotomy, epidural hematoma, incomplete decompression, infection, facet joint injury, neural injury, increased epidural pressure, and postoperative instability. Favorable indications for a biportal endoscopic approach are central lumbar, lateral recess, foraminal, extraforaminal stenoses, and the Bertolotti syndrome. Incidental durotomy and postoperative epidural hematomas are common complications of biportal endoscopic decompression.

Complications of Unilateral Biportal Endoscopic Lumbar Discectomy: A Systematic Review

In recent years, biportal endoscopic surgery has gained popularity, and the number of publications on it has also increased. We herein aimed to investigate the complications of biportal endoscopic surgery. In this study, the available literature was reviewed systematically and the published complications of discectomy in biportal endoscopic spinal surgery were summarized. A systematic search of the literature published until December 31, 2021, was performed using the PubMed, Cochrane Library, Embase, and Web of Science databases. Studies on spinal discectomy using the biportal method were included. Twenty-two articles were finally included for review. The reported complication rate of this procedure was 0%-23.6% (radiological hematoma). In most studies, the complication rate was less than 11%. The mean complication rate was 5.37% when 596 patients (from 16 studies) underwent unilateral biportal endoscopic discectomy for the treatment of lumbar disk herniation. The reported complications of this procedure included dural tear, hematoma, incomplete decompression, recurrence, instability, neurological complications (post-op paresthesia, dysthesia or numbness, or root injury), pseudomeningocele, ascites, infection, retinal hemorrhage, and burn injury. The complication rate was higher in the early learning curve. Unilateral biportal endoscopic discectomy has an acceptable complication rate. Knowing the possible complications and risks of this procedure could help surgeons in taking measures to avoid common complications.

Endoscopic Techniques for Spinal Oncology: A Systematic Literature Review.

Due to its ultraminimally invasive nature, endoscopic spinal surgery is an attractive tool in spinal oncologic care. To date, there has been no comprehensive review of this topic. The authors therefore present a thorough search of the medical literature on endoscopic techniques for spinal oncology. A systematic review using PubMed was conducted using the following keywords: endoscopic spine surgery, spinal oncology, and spinal tumors. Collectively, 19 cases described endoscopic spine surgery for spinal oncologic care. Endoscopic spine surgery has been employed for the care of patients with spinal tumors under the following 4 circumstances: (1) to obtain a reliable tissue diagnosis; (2) to serve as an adjunct during traditional open surgery; (3) to achieve targeted debulking; or (4) to perform definitive resection. These cases employing endoscopic techniques highlight the versatility of this approach and its utility when applied to the right patient and with an experienced surgeon. Our systematic review suggests that, given the right patient and an experienced surgeon, endoscopic spine surgery should be considered in the armamentarium for spinal oncologic care for both staging and definitive resection. This systematic literature review showed that endoscopic techniques have been successfully applied across the spectrum of care in spinal oncology, from diagnosis to definitive treatment.

Long-Term Reoperation Rates After Open versus Minimally Invasive Spine Surgery for Degenerative Lumbar Disease: Five Year Follow-Up of 2130 Patients

Minimally Invasive Spine Surgery (MISS) is a growing alternative to Open Spine Surgery (OSS). The preservation of musculature and minimization of iatrogenic injury is hypothesized to decrease the need for reoperation by preserving normal anatomy. Our objective is to compare the relative long-term reoperation rates after MISS and OSS for the treatment of degenerative disease of the lumbar spine. This retrospective analysis compares the long-term reoperation rates after MISS and OSS. Eligible patients were adults with a primary lumbar intervention carried out between 5/1/2004 and 1/31/2014 to allow for at least 5years of follow up. Patients without sufficient descriptive metrics or follow-up data were excluded. The primary outcome was the rate of lumbar spine reoperation. A total of 2130 patients met the inclusion criteria-1895 underwent OSS and 235 underwent MISS. On average and across all surgery types (decompression and decompression with fusion), 28% of OSS patients required reoperation during the minimum 5-year follow up period while only 14% of MISS patients required reoperation (P= 0.001). The MISS group was statistically identical to the OSS group in all categories except that the MISS group was on average 1.8years older (62.25 vs. 60.45, P= 0.039) and had a higher incidence of diabetes (26% vs. 17%, P= 0.000), but had a lower average body mass index than the OSS group (28.35 vs. 29.60, P= 0.002). In the setting of degenerative lumbar spine disease, MISS has the potential to reduce the long-term need for reoperation when compared with OSS.

Risk Factors in the Prediction of Leg Numbness after Spinal Endoscopic Surgery: Evaluation and Development of a Nomogram.

This study aims at constructing a clinical predictive model that predicted the risk factors for leg numbness after spinal endoscopic surgery. We collected the clinical data of patients, including general information, imaging parameters, and clinical score, from our hospital's electronic database. Based on the postoperative leg numbness visual analog scale (LN-VAS), the clinical data were divided into the leg numbness group (≥25) and the improvement group (<25). All parameters were included in the least absolute shrinkage and selection operator (LASSO) regression analysis, while the parameters with the area under the curve (AUC) greater than 0.7 were selected to construct nomograms. Furthermore, the accuracy and validity of the model were evaluated using the C-index, decision curve analysis (DCA), calibration curve, and receiver operating characteristic curve (ROC). A total of 73 patients' clinical data were included in the training set, where 51 patients were assigned to the improvement group and 22 to the leg numbness group. The nomogram was constructed using four selected parameters, including symptom duration, lumbar spinal stenosis (LSS), pelvic incidence (PI), and preoperative low back pain visual analog scale (LBP-VAS). The nomogram predictions were found to range between 0.01 and 0.99. The values of the C-index, AUC, and internally validated C-index were 0.96, 0.96, and 0.94, respectively. Our result showed that the clinical net benefit of the nomogram ranged between 0.01 and 0.99. Our clinical prediction model demonstrated high predictive ability and clinical validity. Moreover, we found that symptom duration, LSS, PI, and preoperative LBP-VAS were the predictive risk factors for leg numbness after spinal endoscopic surgery.

Complications of Unilateral Biportal Endoscopic Spinal Surgery for Lumbar Spinal Stenosis: A Meta-Analysis and Systematic Review

In recent years, unilateral biportal endoscopic spinal surgery has been used for the treatment of lumbar spinal stenosis with good results. Some investigators counted the total incidence of complications in unilateral biportal endoscopic surgery for lumbar spinal stenosis, but none have analyzed the incidence of specific complications. The present study further counted the incidence of specific complications and gave the possible causes of the complications. English databases including PubMed were searched to collect relevant literature on unilateral biportal endoscopic spinal surgery for lumbar spinal stenosis. The inquiry period is from January 1, 2015, to July 1, 2022. The literature was screened, information extracted, and risk of bias evaluated by the researchers, followed by Meta analysis using R4.2.1 and RStudio statistical software. In total, we included 14 studies involving 707 patients. The included studies were retrospective case series, The results of the single-arm rate meta-analysis showed that the total complication rate of unilateral biportal endoscopic surgery treatment of lumbar spinal stenosis was 8.1% (95% confidence interval [CI] [0.060; 0.103]); of which, the highest incidence of dural tear was 4.5% (95% CI [0.030; 0.064]), the incidence of symptomatic postoperative spinal epidural hematoma was approximately 1.1% (95% CI [0.001; 0.027]), the incidence of incomplete decompression was 2.0% (95% CI [0.007; 0.038]), the incidence of transient palsy was 2.6% (95% CI [0.005; 0.057]). The incidence of total complications of unilateral biportal endoscopic surgery for lumbar spinal stenosis was 8.1%, dural tear remained a major complication with an incidence of 4.5%, incomplete decompression was 2.0%, transient palsy was 2.6%, and, unexpectedly, symptomatic postoperative spinal epidural hematoma was only 1.1%.

Minimally Invasive Transforaminal Lumbar Interbody Fusion with Enhanced Recovery after Surgery (ERAS): Early Experience with Initial Consecutive Cases at a Spine Naïve Community Hospital

Objective: The objective of this study was to examine a spine naïve community hospital’s ability to perform MITLIF safely and with speedy discharge via implementation of a minimally invasive spine surgery (MISS) program utilizing ERAS. Methods: Single community hospital retrospective cohort analysis for initial consecutive MITLIF cases with unilateral pedicle screws performed by a single surgeon from October 2019 to March 2021. Minimum postoperative follow-up was one year. Narcotic use was assessed per the state prescription drug monitoring program. Surgery protocol included single paraspinal incision, non-expandable 18/22 mm tube, operating microscope, fluoroscopic guidance, EMG with SSEP monitoring and Enhanced Recovery After Surgery (ERAS) protocol. Results: 52 patients were included. Average OR time, and fluoroscopy time were 143±115 minutes, and 1.00±0.47 minutes, respectively. Patients were prescribed an average of 38±33 post-operative opioid doses for an average of 8±7 days. All patients on preoperative, chronic narcotics had no prescription changes, pre-op versus post-op, despite clinical improvement. Complications included one irrigation a(1.9%) nd debridement with retention of hardware for surgical site infection, and one revision(1.9%) for displaced hardware. Discharge data included 47 (90.4%), four (7.7%), and one patients (1.9%) discharged on POD1, POD2, and beyond POD2, respectively.Conclusion: MITLIF can be safely and successfully performed at a spine naïve community hospital with excellent intraoperative metrics, a low complication rate, and speedy discharge. MITLIF performed well in multiple perioperative and postoperative variables compared to MISS techniques. Considerations for implementation of MITLIF in the community setting include special equipment, personnel training, surgeon experience, ERAS protocols and diligent patient/indication selection.

The clinical efficacy of biportal endoscopy is comparable to that of uniportal endoscopy via the interlaminar approach for the treatment of L5/S1 lumbar disc herniation.

ObjectiveTo compare the clinical outcomes of unilateral biportal endoscopy/biportal endoscopic spinal surgery (UBE/BESS) via the posterior approach with those of interlaminar endoscopic lumbar discectomy (IELD) for the treatment of L5/S1 lumbar disc herniation.MethodsWe collected the clinical data of patients with L5/S1 lumbar disc herniation who had undergone endoscopic surgery at our center from January 2020 to July 2021, and 92 patients were included. They were divided into UBE/BESS (n = 42) and IELD (n = 50) groups. The incision length, operative time (overall operative, extracanal operative, and intracanal decompression times), intraoperative radiation exposure dose, changes in hemoglobin before and after surgery, postoperative hospital stay, visual analog scale (VAS) score for low back pain and leg, and Oswestry disability index (ODI) were statistically analyzed.ResultsOne case incurred dural tear in the UBE/BESS group, and one case developed recurrence in the IELD group. Postoperatively, the VAS score and ODI index decreased significantly in both groups (P < 0.01). VAS and ODI scores (preoperative as well as 3 days, 3 months, 6 months, and 12 months after surgery), the overall operative time, and postoperative hospital stay were not significantly different between the two groups (P > 0.05). No statistical difference in intraoperative radiation exposure dose was noted between the two groups (P > 0.05). The surgical incision length was greater in the UBE/BESS group (P < 0.01), and pre- and postoperative hemoglobin changes were more pronounced in the UBE/BESS group (P < 0.01). The UBE/BESS group had a longer extracanal operative time and shorter intracanal decompression time (P < 0.01).ConclusionsThe clinical efficacy of UBE/BESS for L5/S1 lumbar disc herniation is comparable to that of IELD. Intraoperative radiation exposure doses were similar in both techniques. UBE/BESS required more time to identify tissue structures and a larger working space when operating outside the spinal canal; however, the efficiency of nucleus pulposus removal and nerve root release inside the spinal canal superseded that in IELD. Furthermore, the surgical incision in the UBE/BESS technique was longer, with greater actual blood loss during surgery, thus rendering UBE/BESS inferior to the IELD technique in terms of surgical trauma. Nonetheless, no significant difference was noted between the two techniques in the postoperative recovery time of patients.

Mapping knowledge structure and themes trends in unilateral biportal endoscopic spine surgery: A bibliometric analysis.

BackgroundThe numerous benefits of unilateral biportal endoscopic (UBE) spine surgery have attracted the attention of many researchers, and a considerable number of relevant clinical studies have been published. However, global research trends in the field of UBE have received little attention. The purpose of this study was to apply bibliometric method to analyze the UBE-related publications to obtain an overview of the research trends in the field of UBE, as well as research hotspots and trends.MethodsWeb of Science database was searched for articles published until January 31, 2022. CiteSpace was used to analyze the data, which provided graphical knowledge maps. The following factors were applied to all literature: number of publications, distribution, h-index, institutions, journals, authors, and keywords.ResultsSeventy-three articles were identified. Since 2019, there has been a significant increase in the number of UBE-related publications. The country with the largest number of articles was South Korea (72.6%), followed by China (9.6%), Japan (4.1%), and Egypt (4.1%). South Korea had the highest h-index (16), followed by China (2), Japan (1), and Egypt (1). Leon Wiltse Memorial Hospital was the organization that produced the most papers (12 publications). Heo DH was the most productive author (16 papers) and was the most cited author (35 times). World Neurosurgery published the most papers on UBE (23.3%). The main research hotspots were spinal diseases, decompression, complications, learning curve, and interbody fusion. In addition, the recent concerns were “learning curve,” “interbody fusion,” “management,” and “dural tear.”ConclusionsThe quantity of publications on UBE research will increase, and South Korea being the major contributor and most prominent country in this field. The findings of our study will provide researchers with practical information on the field of UBE, and identification of mainstream research directions and recent hotspots.

Percutaneous full-endoscopic uniportal decompression for the treatment of symptomatic idiopathic lumbar spinal epidural lipomatosis: Technical note.

BackgroundLumbar spinal epidural lipomatosis (SEL) is a rare condition characterized by an excessive accumulation of adipose tissue within the spinal canal, compressing the dura sac and/or nerve roots. When conservative treatments fail and clinical symptoms progress quickly and seriously, surgical decompression should be considered. With the rapid development of endoscopic armamentaria and techniques, the pathological scope that can be treated by percutaneous endoscopic spine surgery is ever expanding.ObjectiveIn this paper, the authors describe a patient with lumbar spinal epidural lipomatosis who was treated with a percutaneous full-endoscopic uniportal decompression surgery successfully. This article aims to validate the feasibility of percutaneous full-endoscopic uniportal decompression for the treatment of symptomatic idiopathic spinal epidural lipomatosis via interlaminar approach.MethodsWe describe a case of a 69-year-old man with a 10-year history of low back pain, intermittent claudication, and bilateral leg neuropathic pain. He was diagnosed with lumbar epidural lipomatosis, which did not respond to conservative therapy. After a comprehensive evaluation, he underwent percutaneous endoscopic spine surgery to remove hyperplastic adipose tissue and decompress nerve roots and dura sac.ResultsThe patient was treated with a percutaneous full-endoscopic uniportal decompression surgery successfully. After the procedure, his leg pain decreased and his walking capacity improved. There were no surgery-related complications, such as cerebrospinal fluid leakage, incision infection, etc.ConclusionsThe case with SEL was successfully treated with a percutaneous full-endoscopic uniportal surgery, which has the advantages of excellent presentation of anatomical structures, expanded field of vision, less surgical-related trauma, and bleeding. The key point of the procedure is to release and cut off the bands which divide the epidural space into small rooms filled with excess adipose tissue.

Current Status and research hotspots in the field of full endoscopic spine surgery: A bibliometric analysis.

PurposeWe aimed to comprehensively analyze the current status, hotspots, and trends in full endoscopic spine surgery (FESS) research using bibliometric analysis and knowledge domain mapping.MethodsThe Web of Science database was used to screen FESS-related articles published between January 1, 1993 and June 10, 2022. The evaluation involved the following criteria: total number of articles; H-index; and contributions from countries/regions, institutions, journals, and authors.ResultsA total of 1,064 articles were included. Since 2016, there have been a significant number of publications in the field of FESS. The country/region contributing the largest number of articles was China (37.8%), followed by South Korea (24%), the United States (16.1%), Japan (5.7%), and Germany (5.1%). South Korea (35) had the highest H-index, followed by the United States (27), China (22), Japan (21), and Germany (20). World Neurosurgery (15.7%) published the largest number of FESS-related articles. However, among the top 10 most cited articles, six were published in Spine. The author who contributed the most was S.H. Lee (5.4%), and the largest number of contributions in this field originated from Wooridul Spine Hospital (South Korea; 6.1%). Notably, six of the 10 most published authors in this field were from South Korea. Of the top five productive institutions, three were from South Korea. The keywords with the strongest citation bursts in the field of FESS were “lumbar spine,” “discectomy,” “interlaminar,” “surgical technique,” “follow-up,” “excision,” “thoracic spine,” and “endoscopic surgery.” The 10 clusters generated in this study were: “endoscopic discectomy” (#0), “thoracic myelopathy” (#1), “recurrent lumbar disc herniation” (#2), “low back pain” (#3), “cervical vertebrae” (#4), “lumbar spinal stenosis” (#5), “transforaminal lumbar interbody fusion” (#6), “radiation exposure” (#7), “management” (#8), and “lumbar spine” (#9).ConclusionGlobal research on FESS is mostly concentrated in a few countries/regions and authors. South Korea has made the largest contribution to the field of FESS. Based on the most cited keyword bursts and clusters, the focus of FESS research was found to include its indications, management, and applications.

Intraoperative CT-guided navigation versus fluoroscopy for percutaneous pedicle screw placement in 192 patients: a comparative analysis

BackgroundPercutaneous pedicle screw (PPS) placement is a key step in several minimally invasive spinal surgery (MISS) procedures. Traditional technique for PPS makes use of C-arm fluoroscopy assistance (FA). More recently, newer intraoperative imaging techniques have been developed for PPS, including CT-guided navigation (CTNav). The aim of this study was to compare FA and CTNav techniques for PPS with regard to accuracy, complications, and radiation dosage.Materials and methodsA total of 192 patients with degenerative lumbar spondylolisthesis and canal stenosis who underwent MISS posterior fusion ± interbody fusion through transforaminal approach (TLIF) were retrospectively reviewed. Pedicle screws were placed percutaneously using either standard C-arm fluoroscopy guidance (FA group) or CT navigation (CTNav group). Intraoperative effective dose (ED, mSv) was measured. Screw placement accuracy was assessed postoperatively on a CT scan using Gertzbein and Robbins classification (grades A–E). Oswestry disability index (ODI) and visual analog scale (VAS) scores were compared in both groups before and after surgery.ResultsA total of 101 and 91 procedures were performed with FA (FA group) and CTNav approach (CTNav group), respectively. Median age was 61 years in both groups, and the most commonly treated level was L4–L5. Median ED received from patients was 1.504 mSv (0.494–4.406) in FA technique and 21.130 mSv (10.840–30.390) in CTNav approach (p < 0.001). Percentage of grade A and B screws was significantly higher for the CTNav group (96.4% versus 92%, p < 0.001), whereas there were 16 grade E screws in the FA group and 0 grade E screws in the CTNav group (p < 0.001). A total of seven and five complications were reported in the FA and CTNav group, respectively (p = 0.771).ConclusionsCTNav technique increases accuracy of pedicle screw placement compared with FA technique without affecting operative time. Nevertheless, no significant difference was noted in terms of reoperation rate due to screw malpositioning between CTNav and FA techniques. Radiation exposure of patients was significantly higher with CTNav technique.Level of Evidence: Level 3.

Navigation Techniques in Endoscopic Spine Surgery.

Endoscopic spine surgery (ESS) advances the principles of minimally invasive surgery, including minor collateral tissue damage, reduced blood loss, and faster recovery times. ESS allows for direct access to the spine through small incisions and direct visualization of spinal pathology via an endoscope. While this technique has many applications, there is a steep learning curve when adopting ESS into a surgeon's practice. Two types of navigation, optical and electromagnetic, may allow for widespread utilization of ESS by engendering improved orientation to surgical anatomy and reduced complication rates. The present review discusses these two available navigation technologies and their application in endoscopic procedures by providing case examples. Furthermore, we report on the future directions of navigation within the discipline of ESS.

Clinical Features and Management of Seizure After Percutaneous Endoscopic Spine Surgery: A Retrospective Case Series Analysis

To describe the perioperative clinical features, management, and outcomes of patients with seizure after percutaneous endoscopic spine surgery (PESS). Patients who experienced seizure after PESS in a tertiary orthopedic hospital between January 2016 and June 2022 were retrospectively recruited, and patient charts were reviewed. Twenty-nine patients were recruited, and the incidence of seizure after PESS was 0.52%. The operation time was 110.0 minutes (interquartile range [IQR], 82.5-235.0 minutes) and the irrigation speed was 109.0 mL/minute (IQR, 86.5-145.5 mL/minute). Definitive dural tears were reported in 15 patients (51.7%). In addition to agitation and myotonia, significant increased respiratory rate (29.9 ± 6.5 breaths/minute), tachycardia (112.1 ± 20.6 beats/minute), and hypertension (systolic, 189.5 ± 21.9 mm Hg; diastolic, 98.3 ± 10.6 mm Hg) were observed. Arterial blood gas analysis showed hypocapnia, metabolic acidosis, and hyperlactatemia. All patients received analgesia and sedation as well as hyperosmolar therapy. The estimated duration of seizure was 3.0 hours (IQR, 2.5-4.0 hours) and the postoperative length of hospital stay was 3.0 (IQR, 3.0-5.5) days. The Japanese Orthopaedic Association score and visual analog scale score improved markedly within 6 months after surgery. Despite the low incidence and short duration, seizure after PESS should be considered a critical and urgent syndrome. Management strategies for seizure mainly involve intensive care, securing the airway, analgesia and sedation, hyperosmolar therapy, and negative fluid balance. No significant adverse effects of seizure on clinical outcomes were observed during 6 months of follow-up.

211. Assessing the economic benefit of robotic and navigational assistance in surgical treatment of L4-L5 spondylolisthesis: is higher upfront equipment cost worth the operative and safety benefits?

<h3>BACKGROUND CONTEXT</h3> The use of robotic or navigational guidance has seen tremendous growth in recent years in minimally invasive spine surgery (MISS) due to its ability to reduce operative time, increase patient safety, and aid in surgical accessibility, especially in high incidence pathologies. However, there remain considerable gaps in the literature in regards to the cost-effectiveness of robotic or navigational guidance in the surgical treatment of L4-L5 spondylolisthesis. <h3>PURPOSE</h3> To assess differences in patient outcomes and relative cost effectiveness in L4-L5 spondylolisthesis patients treated using robotic or navigational guidance in MISS procedures. <h3>STUDY DESIGN/SETTING</h3> Retrospective review of prospective MISS database. <h3>PATIENT SAMPLE</h3> A total of 524 MISS patients. <h3>OUTCOME MEASURES</h3> HRQLs, complications, surgical factors. <h3>METHODS</h3> MISS patients with preoperative diagnoses of L4-L5 spondylolisthesis and baseline (BL) and 2-year (2Y) postoperative radiographic/HRQL data were included. Patients were split between those operated on using robotic or navigational guidance (Robotic+) or not (Robotic-). Means comparison analysis assessed differences in radiographic and clinical outcomes at BL, 1Y and 2Y postoperatively. Costs were calculated using the PearlDiver database through estimates from Medicare payscales for services within a 30-day window, including estimates regarding costs of postoperative complications, outpatient healthcare encounters, revisions and medical related readmissions. Quality-adjusted life years (QALYs) was calculated using NDI mapped to SF6D using validated methodology and utilized a 3% discount rate to account for residual decline to life expectancy (78.7 years). <h3>RESULTS</h3> Eighty-eight patients (54.40±12.49 years, 40% female, 30.93±6.52 kg/m², mean CCI: 2.23±1.55) with L4-5 spondylolisthesis were included. At baseline, patients were comparable in age, gender, BMI and CCI (all p>.05). Similarly, patients did not differ significantly in baseline regional nor global radiographic deformity (all p>.05). Perioperatively, Robotic+ patients were significantly less likely to undergo corpectomy (p=.006), and also demonstrated significantly lower EBL (p=.013) and operative time (p=.009). Economic analysis revealed broad cost savings for Robotic+ patients. Specifically, Robotic+ patients demonstrated increased utility gained per QALYs at 1Y (p=.028), as well as Life Expectancy QALYs (p=.002). Furthermore, Robotic+ patients were significantly more likely to demonstrate increased QALYs gained by 2Y (p=.029). Conversely, overall cost per QALY by 2Y was significantly higher for Robotic- patients, which resulted in an approximately 6.5x greater cost per QALY for such patients (76,848 vs 11,839 USD). Overall, Robotic+ patients demonstrated significantly higher cost-effectiveness by 2Y (p<.001). <h3>CONCLUSIONS</h3> Corrective procedures for the treatment of L4-L5 spondylolisthesis and other common spinal pathologies has seen significant growth in the uptake of novel technologies such as robotic or navigational assistance. Though robotic and navigational assistance systems have a significantly higher upfront cost compared to existing techniques, our findings demonstrate reductions in intraoperative invasiveness and OR time pay great dividends in demonstrating the 2Y cost-effectiveness of such novel technologies in minimally-invasive adult spinal deformity surgery. <h3>FDA DEVICE/DRUG STATUS</h3> This abstract does not discuss or include any applicable devices or drugs.

219. Comparative analysis of prone lateral versus single position lateral decubitus positioning in achieving optimal outcomes and reducing complication rates in minimally invasive spine surgery

<h3>BACKGROUND CONTEXT</h3> Recent literature has pointed to the rising use of prone lateral versus lateral decubitus positioning in minimally invasive spine surgery (MISS) as a method to reduce operative time, increase patient safety, and aid in surgical accessibility. However, there is a paucity of literature as to how prone lateral and lateral decubitus positioning compares in terms of reaching optimal postoperative outcomes and reducing complication rates. <h3>PURPOSE</h3> To assess differences between prone lateral and single-position lateral decubitus positioning compares in terms of reaching optimal postoperative outcomes and reducing complication rates. <h3>STUDY DESIGN/SETTING</h3> Retrospective review of prospective MIS database. <h3>PATIENT SAMPLE</h3> A total of 524 MIS patients. <h3>OUTCOME MEASURES</h3> HRQLs; complications; surgical factors. <h3>METHODS</h3> MISS patients with BL) and 2-year(2Y) postop radiographic/HRQL data were included. Patients positioned in the prone latera (PL) or single-position lateral decubitus (LD) position were isolated. At 2Y, an optimal outcome score was calculated using 4 equally weighted criteria: 1) achieving ideal PT per SRS-Schwab at 2Y, 2) Achieving ideal PI-LL per SRS-Schwab at 2Y, 3) No complication requiring reoperation, 4) Achieving NRS MCID by Salaffi et al. criteria; optimal score threshold was set at meeting 2 of 4 criteria. Means comparison analysis assessed differences in radiographic and clinical outcomes at BL and 1Y postoperatively. ANCOVA assessed estimated marginal means adjusting for BL age and revision status. <h3>RESULTS</h3> Thirty-four PL and 36 LD patients were included (54.40±12.49 years, 40% female, 30.93±6.52 kg/m2, mean CCI: 2.23±1.55) were included. At baseline, patients were comparable in age, gender, BMI and CCI (all p>.05). Perioperatively, PL patients demonstrated significantly lower operative time (200.09 vs 284.54 min, p=.007) and EBL (332.35 vs 192.05 mL, p=.027). Though optimization scores were equivalent between groups (p=.160), PL patients demonstrated significantly lower perioperative complication rates (p=.012), neurological complication rates (p=.006), and had a fewer number of total complications by 2Y (p=.014). When controlling for BL age and revision status, the PL patients demonstrated consistently fewer intra- and perioperative complications as well (both p<.015). In terms of patient-reported outcomes, PL patients also demonstrated significantly improved NRS-Leg scores compared to LD patients by 1Y (p=.038). <h3>CONCLUSIONS</h3> Patients placed in the PL position during minimally-invasive adult spinal deformity surgery demonstrate decreased mean operative times and decreased intraoperative invasiveness and blood loss versus patients operated on via single-position LD positioning. Though overall rates of achieving optimal outcome remain comparable, PL approach should be considered as there may be significant additional benefit in reducing peri- and postoperative complications by 2Y. <h3>FDA DEVICE/DRUG STATUS</h3> This abstract does not discuss or include any applicable devices or drugs.

220. An analysis of intraoperative neurophysiological monitoring events during single position minimally invasive spine surgery

<h3>BACKGROUND CONTEXT</h3> The single position minimally invasive (MIS) lateral approach allows access to the anterior and posterior columns with the patient positioned in the lateral decubitus position. The purpose of this approach was to mitigate complications associated with open procedures while achieving circumferential fusion. More recently, an alternative prone-lateral technique has been developed streamlining surgical access with potential advantages. The purpose of this study was to identify differences in intraoperative neurophysiological monitoring (IOM) event rates between single position lateral decubitus and prone-lateral patients during MIS spine surgery. <h3>PURPOSE</h3> To determine if lateral decubitus positioning will correlate with the occurrence of neurophysiological monitoring events during MIS spine surgery. <h3>STUDY DESIGN/SETTING</h3> Retrospective cohort. <h3>PATIENT SAMPLE</h3> A total of 524 MIS patients were included. <h3>OUTCOME MEASURES</h3> Intraoperative neurophysiological monitoring, lateral decubitus, prone lateral. <h3>METHODS</h3> MIS spine surgery patients with available surgical positioning and IOM data were included if they were in a single position. Patients were stratified into 2 groups based on operative positioning: lateral decubitus (Lat) and prone lateral (PL). IOM was performed using somatosensory evoked potentials (SSEPs) and electromyography (EMG) techniques. An abnormal event was defined as any confirmed loss of signal during the operative period in the anatomical distribution of the surgery. Means comparison tests and multivariable logistic regression analysis assessed differences between patient groups. <h3>RESULTS</h3> Of 524 patients eligible, 226 (43.1%) had available positioning and IOM data. Of these, 88 met inclusion criteria (52 Lat and 36 PL). The majority were male (49, 55.7%), mean age of 49.2 yrs and 2.0 levels fused and 18 (20.5%) undergoing an osteotomy. In total, 19 (21.6%) patients had an abnormal IOM event. There was a significant difference in abnormal IOM event rates for patients who were in Lat (31%) and PL (8%) positioning, p=0.012. Multivariable analysis adjusting for surgical invasiveness showed that PL patients were 76.8% less likely to experience an abnormal IOM event than Lat patients (OR .232 [CI .060-.905], p=.035). Of the Lat patients with an abnormal IOM, 6.3% had postoperative sensory loss in the saphenous nerve. <h3>CONCLUSIONS</h3> Lateral decubitus positioning appears to be independently associated with abnormal intraoperative neurophysiological monitoring events when compared to prone lateral positioning during MIS. This has the potential to help with risk stratification in the future when determining patients undergoing a single position procedure. <h3>FDA DEVICE/DRUG STATUS</h3> This abstract does not discuss or include any applicable devices or drugs.

112. The effect of preoperative rehabilitation on minimally invasive spine surgery patient outcomes

<h3>BACKGROUND CONTEXT</h3> Minimally invasive (MIS) spine surgery techniques were developed to mitigate complications associated with open procedures while achieving functional outcomes. More recently, preoperative rehabilitation programs have been implemented to prepare patients for surgery and to promote patient health. The purpose of this study was to identify the effect of preoperative rehabilitation on MIS spine surgery patient outcomes. <h3>PURPOSE</h3> Identify if preoperative rehabilitation influences patient outcomes following MIS spine surgery. <h3>STUDY DESIGN/SETTING</h3> Retrospective cohort. <h3>PATIENT SAMPLE</h3> This study included 524 MIS patients. <h3>OUTCOME MEASURES</h3> Preoperative rehabilitation, perioperative complications, patient outcomes. <h3>METHODS</h3> MIS spine surgery patients with baseline (BL) and two-year (2Y) follow-up were included if they had preoperative rehabilitation data. Patients were divided into two groups: those who had preoperative rehabilitation [Prehab] and those who did not [no Prehab]. Prehab consisted of physical and mental components, ie, physical therapy for 3 months, 3 days a week for core, paraspinal and leg strengthening, with a review of postop protocols to do at home, including gait and balance training. Patients were also referred for cognitive behavioral therapy for 2 weeks to prepare for the stress of surgery. Patients were excluded if they presented with any of the following at baseline: severe neurological deficit (< 3/5), minimal ambulation, or current depression/anxiety. Means comparison tests and logistic regression analysis controlling for age, CCI, ASA grade, and invasiveness assessed differences between patient groups. Conditional inference tree (CIT) analysis determined thresholds for continuous variables. <h3>RESULTS</h3> A total of 216 patients met inclusion criteria (76 Prehab, 140 no Prehab). The majority were male (97, 44.9%), mean age of 55.17 years, and 2.3 levels fused and 28 (13.0%) undergoing 3-CO. There was a significant difference in LOS for patients who had (3.6 days) and didn't have (5.3 days) Prehab, p <.05. Multivariate regression showed that Prehab was an independent predictor of a shorter LOS (OR .686 [CI .484-.972], p=.034). CIT analysis determined Prehab patients were 85.0% less likely to have a LOS greater than 2.0 days (OR .015 [CI .001-.258], p=.004). By 2 years, Prehab patients had lower rates of readmissions (6.7% vs 20.0%) and reoperations (4.0% vs 15.3%) than no Prehab patients, both p <.05. <h3>CONCLUSIONS</h3> Preoperative rehabilitation appears to be independently associated with a shorter length of stay following minimally invasive spine surgery. Patients who had preoperative rehabilitation also had lower rates of readmissions and reoperations by two years postoperatively. <h3>FDA DEVICE/DRUG STATUS</h3> This abstract does not discuss or include any applicable devices or drugs.

P117. An evaluation of preoperative patient weight and body mass index during single-position minimally invasive spine surgery

<h3>BACKGROUND CONTEXT</h3> The single position minimally invasive (MIS) approach allows access to the anterior and posterior columns with the ability to mitigate complications associated with open procedures while achieving circumferential fusion. The purpose of this study was to identify if patient weight or body mass index (BMI) leads to differences in intraoperative event rates. <h3>PURPOSE</h3> To determine if patient weight and BMI will correlate with the occurrence of intraoperative events during MIS spine surgery. <h3>STUDY DESIGN/SETTING</h3> Retrospective cohort. <h3>PATIENT SAMPLE</h3> A total of 524 MIS patients. <h3>OUTCOME MEASURES</h3> Weight (kg), BMI (kg/m2), Aborted procedures, estimated blood loss (EBL), operative time (OpTime). <h3>METHODS</h3> Of 524 patients eligible, 226 (43.1%) had available data. Of these, 88 met inclusion criteria (52 Lat and 36 PL). The majority were male (49, 55.7%), mean age of 49.2 yrs and 2.0 levels fused and 18 (20.5%) undergoing an osteotomy. Lat patients with a weight > 130 kg had significantly longer OpTime (p=0.003) and more EBL (p=0.019). There was a significant difference in mean weight for lat patients with (121.8 kg) and without (97.7 kg) an aborted procedure, p=0.021. There was also a significant difference in mean BMI for lat patients with (35.3 kg/m2) and without (29.6 kg/m2) an aborted procedure, p=0.015. Multivariable analysis showed that weight (OR 1.03 [CI 1.01-1.06], p=.020) and BMI (OR 1.15 [CI 1.02-1.30], p=.026) were independent predictors for aborted procedures in lat patients. In an analysis of PL patients, there was one aborted case (weight > 120 kg), but no significant findings for EBL or OpTime. <h3>RESULTS</h3> Of 524 patients eligible, 226 (43.1%) had available data. Of these, 88 met inclusion criteria (52 Lat and 36 PL). The majority were male (49, 55.7%), mean age of 49.2 yrs and 2.0 levels fused and 18 (20.5%) undergoing an osteotomy. Lat patients with a weight > 130 kg had significantly longer OpTime (p=0.003) and more EBL (p=0.019). There was a significant difference in mean weight for lat patients with (121.8 kg) and without (97.7 kg) an aborted procedure, p=0.021. There was also a significant difference in mean BMI for lat patients with (35.3 kg/m2) and without (29.6 kg/m2) an aborted procedure, p=0.015. Multivariable analysis showed that weight (OR 1.03 [CI 1.01-1.06], p=.020) and BMI (OR 1.15 [CI 1.02-1.30], p=.026) were independent predictors for aborted procedures in lat patients. In an analysis of PL patients, there was one aborted case (weight > 120 kg), but no significant findings for EBL or OpTime. <h3>CONCLUSIONS</h3> Weight and BMI appear to be independently associated with aborted procedures for patients in the lateral decubitus position during minimally invasive spine surgery. Patients in the lateral decubitus position who weighed 130 kg or more had on average longer operative times and more estimated blood lost. This study has the potential to help with risk stratification in the future when determining patients undergoing a single position procedure. <h3>FDA DEVICE/DRUG STATUS</h3> This abstract does not discuss or include any applicable devices or drugs.

197. Subtherapeutic perioperative levels of cefuroxime inside cannulated pedicle screw commonly used in spine surgery: results from an experimental microdialysis study

BACKGROUND CONTEXT Despite minimal invasive spine techniques, postoperative implant associated vertebral osteomyelitis remains a risk of great morbidity for the patient. Perioperative antibiotic prophylaxis is important for prevention of postoperative infection and local tissue concentrations can be measured with microdialysis. We hypothesized that cefuroxime concentrations in relation to a cannulated pedicle screws may be insufficient for prevention of postoperative infection. PURPOSE The aim was to compare perioperative cefuroxime concentrations inside a cannulated pedicle screw to the adjacent noninstrumented lumbar vertebral pedicle. STUDY DESIGN/SETTING In vivo experimental pharmacokinetics study of cefuroxime concentrations in an acute preclinical porcine model. PATIENT SAMPLE Not applicable. OUTCOME MEASURES The primary end-point was the time above cefuroxime clinical breakpoint minimal inhibitory concentration for Staphylococcus aureus of 4 µg/mL (T>MIC4) METHODS Microdialysis probes were placed in a cannulated pedicle screw and the adjacent non-instrumented lumbar vertebral pedicle (L1) in 8 female pigs through a surgical posterior open lumbar approach. Following a single-dose intravenous cefuroxime administration (1.5 g), microdialysates and plasma were dynamically sampled over 8 hours. RESULTS Mean T>MIC4 (range) was 123 min (112-175) in plasma, 101 min (68-144) in the non-instrumented vertebral pedicle and 0 min (0-0) inside the cannulated pedicle screw. CONCLUSIONS A single-dose intravenous cefuroxime administration (1.5 g) seems insufficient for antibiotic prophylaxis inside a cannulated pedicle screw placed in the lumbar spine. Sufficient concentrations were achieved in the adjacent non-instrumented vertebral pedicle for up to 1.5-2 hours. Therefore, alternative dosing regimens should be considered in minimal invasive spine surgery longer than 1.5 hours and additional prophylactic strategies against infection may be applied in high-risk patients. FDA DEVICE/DRUG STATUS Cefuroxime (Approved for this indication) Despite minimal invasive spine techniques, postoperative implant associated vertebral osteomyelitis remains a risk of great morbidity for the patient. Perioperative antibiotic prophylaxis is important for prevention of postoperative infection and local tissue concentrations can be measured with microdialysis. We hypothesized that cefuroxime concentrations in relation to a cannulated pedicle screws may be insufficient for prevention of postoperative infection. The aim was to compare perioperative cefuroxime concentrations inside a cannulated pedicle screw to the adjacent noninstrumented lumbar vertebral pedicle. In vivo experimental pharmacokinetics study of cefuroxime concentrations in an acute preclinical porcine model. Not applicable. The primary end-point was the time above cefuroxime clinical breakpoint minimal inhibitory concentration for Staphylococcus aureus of 4 µg/mL (T>MIC4) Microdialysis probes were placed in a cannulated pedicle screw and the adjacent non-instrumented lumbar vertebral pedicle (L1) in 8 female pigs through a surgical posterior open lumbar approach. Following a single-dose intravenous cefuroxime administration (1.5 g), microdialysates and plasma were dynamically sampled over 8 hours. Mean T>MIC4 (range) was 123 min (112-175) in plasma, 101 min (68-144) in the non-instrumented vertebral pedicle and 0 min (0-0) inside the cannulated pedicle screw. A single-dose intravenous cefuroxime administration (1.5 g) seems insufficient for antibiotic prophylaxis inside a cannulated pedicle screw placed in the lumbar spine. Sufficient concentrations were achieved in the adjacent non-instrumented vertebral pedicle for up to 1.5-2 hours. Therefore, alternative dosing regimens should be considered in minimal invasive spine surgery longer than 1.5 hours and additional prophylactic strategies against infection may be applied in high-risk patients.