Study Design. A retrospective cohort study of prospectively collected data. Objective. The aim of this study was to describe the development of and early experience with an evidence-based enhanced recovery after surgery (ERAS) pathway for lumbar decompression. Summary of Background Data. ERAS protocols have been consistently associated with improved patient experience and outcomes, and reduced cost and length of hospital stay (LoS). Despite successes in other orthopedic subspecialties, ERAS has yet to be established in spine surgery. Here, we report the development of and initial experience with the first comprehensive ERAS pathway for MIS lumbar spine surgery. Methods. An evidence-based review of the literature was performed to select components of the ERAS pathway. The pathway was applied to 61 consecutive patients presenting for microdiscectomy or lumbar laminotomy/laminectomy between dates. Data collection was performed by review of the electronic medical record. We evaluated compliance with individual ERAS process measures, and adherence to the overall pathway. The primary outcome was LoS. Demographics, comorbidities, perioperative course, prevalence of opioid tolerance, and factors affecting LoS were also documented. Results. The protocol included 15 standard ERAS elements. Overall pathway compliance was 85.03%. Median LoS was 279 minutes [interquartile range (IQR) 195–398 minutes] overall, 298 minutes (IQR 192–811) for lumbar decompression and 285 minutes (IQR 200–372) for microdiscectomy. There was no correlation between surgical subtype or duration and LoS. Overall, 37% of the cohort was opioid-tolerant at the time of surgery. There was no significant effect of baseline opioid use on LoS, or on the total amount of intraoperative or PACU opioid administration. There were four complications (6.5%) resulting in extended LoS (>23 hours). Conclusion. This report comprises the first description of a comprehensive, evidence-based ERAS for spine pathway, tailored for lumbar decompression/microdiscectomy resulting in short LoS, minimal complications, and no readmissions within 90 days of surgery. Level of Evidence: 3

OBJECTIVEEnhanced recovery after surgery (ERAS) and multimodal analgesia are established care models that minimize perioperative opioid consumption and promote positive outcomes after spine surgery. Opioid-free anesthesia (OFA) is an emerging technique that may achieve similar goals. The purpose of this study was to evaluate an OFA regimen within an ERAS pathway for lumbar decompressive surgery and to compare perioperative opioid requirements in a matched cohort of patients managed with traditional opioid-containing anesthesia (OCA).METHODSThe authors performed a retrospective analysis of prospectively collected data. They included 36 patients who underwent lumbar decompression under their ERAS pathway for spinal decompression between February and August 2018. Eighteen patients who received OFA were matched in a 1:1 ratio to a cohort managed with a traditional OCA regimen. The primary outcome was total perioperative opioid consumption. Postoperative pain scores (measured using the numerical rating scale [NRS]), opioid consumption (total morphine equivalents), and length of stay (time to readiness for discharge) were compared in the postanesthesia care unit (PACU). The authors also assessed compliance with ERAS process measures and compared compliance during 3 phases of care: pre-, intra-, and postoperative.RESULTSThere was a significant reduction in total perioperative opioid consumption in patients who received OFA (2.43 ± 0.86 oral morphine equivalents [OMEs]; mean ± SEM), compared to patients who received OCA (38.125 ± 6.11 OMEs). There were no significant differences in worst postoperative pain scores (NRS scores 2.55 ± 0.70 vs 2.58 ± 0.73) or opioid consumption (5.28 ± 1.7 vs 4.86 ± 1.5 OMEs) in the PACU between OFA and OCA groups, respectively. There was a clinically significant decrease in time to readiness for discharge from the PACU associated with OFA (37 minutes), although this was not statistically significantly different. The authors found high overall compliance with ERAS process measures (91.4%) but variation in compliance according to phase of care. The highest compliance occurred during the preoperative phase (94.71% ± 2.88%), and the lowest compliance occurred during the postoperative phase of care (85.4% ± 5.7%).CONCLUSIONSOFA within an ERAS pathway for lumbar spinal decompression represents an opportunity to minimize perioperative opioid exposure without adversely affecting pain control or recovery. This study reveals opportunities for patient and provider education to reinforce ERAS and highlights the postoperative phase of care as a time when resources should be focused to increase ERAS adherence.

Newer navigation protocols that rely on intraoperative CT registration have improved the accuracy of imaging models and allowed surgeons to rely less on fluoroscopy. Despite concerns regarding ionizing radiation exposure to the patient, use of CT navigation systems was found to reduce radiation exposure by more than 90% compared to traditional fluoroscopic guided percutaneous surgical techniques (1). Furthermore, the surgeon's exposure to radiation is almost eliminated, as the surgeon does not need to be close to the patient during the CT image registration.The accuracy of navigation has also undergone a huge amount of progress. In addition to higher quality registration, the use of stereotactic 3D cameras allows the system to predict relative position between instruments and anatomical landmarks in real time with higher reliability (2). Amiot et al. and Yu et al. (3,4). both demonstrated that freehand pedicle screw (PS) placement had a higher rate of error and reoperation compared to navigation assisted placement. The same results were reflected in a meta-analysis of 12 studies conducted by Shin et al. (5) However, many other meta-analyses in the literature have failed to demonstrate superiority of computer assisted navigation to free hand PS instrumentation perhaps due to the heterogeneity of studies included. The accuracy of navigation has also undergone a lot of progress. In additional to higher quality registration, the use of stereotactic 3D cameras allows the system to predict relative position between instruments and anatomical landmarks in real time with higher reliability (2). Amiot et al. and Yu et al. (3,4) both demonstrated that freehand PS placement had a higher rate of error and reoperation compared to navigation assisted placement. Shin et al. completed a meta-analysis of 12 studies which also reflected the same results (5). However, many other meta-analyses in the literature have failed to demonstrate superiority of computer assisted navigation to free hand PS instrumentation perhaps due to the heterogeneity of studies included.Navigation systems rely on the use of reference trackers to keep the registration image in sync throughout the operation regardless of the positioning of the patient. Multiple modalities of anatomic tracking are in use. Pin trackers that are inserted into bony landmarks allow for accurate mapping with relatively few trackers, however

OBJECTIVEEnhanced recovery after surgery (ERAS) pathways are associated with improved outcomes, lower morbidity and complications, and higher patient satisfaction in multiple surgical subspecialties. Despite these gains, there are few data to guide the application of ERAS concepts to spine surgery. The authors report the development and implementation of the first ERAS pathway for patients undergoing anterior cervical discectomy and fusion (ACDF) and cervical disc arthroplasty (CDA).METHODSThis was a retrospective cohort study of prospectively collected data. The authors created a multidisciplinary pathway based on best available evidence for interventions that positively influence outcomes after anterior cervical spine surgery. Patients were followed prospectively up to postoperative day 90. Patient data were collected via electronic medical record review and included demographics, comorbidities, baseline and perioperative opioid use, postoperative complications, and length of hospital stay (LOS). ERAS process measures and compliance with pathway elements were also tracked.RESULTSThirty-three patients were cared for under the pathway (n = 25 ACDF; n = 8 CDA). The median LOS was 416 minutes (interquartile range [IQR] 210–1643 minutes). Eight patients required an extended stay—longer than 23 hours. Reasons for extended admission included pain (n = 4), dyspnea (n = 1), hypoxia (n = 1), hypertension (n = 1), and dysphagia (n = 1). The median LOS for the 8 patients who required extended monitoring prior to discharge was 1585 minutes (IQR 1423–1713 minutes). Overall pathway compliance with included process measures was 85.6%. The median number of ERAS process elements delivered to each patient was 18. There was no strong association between LOS and number of ERAS process elements provided (Pearson’s r = −0.20). Twelve percent of the cohort was opioid tolerant on the day of surgery. There were no significant differences between total intraoperatively or postanesthesia care unit–administered opioid, or LOS, between opioid-tolerant and opioid-naïve patients. There were no complications requiring readmission.CONCLUSIONSAn ERAS pathway for anterior cervical spine surgery facilitates safe, prompt discharge. The ERAS pathway was associated with minimal complications, and no readmissions within 90 days of surgery. Pain and respiratory compromise were both linked with extended LOS in this cohort. Further prospective studies are needed to confirm the potential benefits of ERAS for anterior cervical spine surgery, including longer-term complications, cost, and functional outcomes.

BACKGROUND Sagittal alignment is an important consideration in spine surgery. The literature is conflicted regarding the effect of minimally invasive transforaminal lumbar interbody fusion (MI-TLIF) on sagittal parameters and the role of expandable cage technology. OBJECTIVE To compare lordosis generated by static and expandable cages and to determine what factors affect postoperative sagittal parameters. METHODS Preoperative regional lordosis (RL), segmental lordosis (SL), and posterior disc height (PDH) were compared to postoperative values in single-level MI-TLIF performed using expandable or static cages. Patients were stratified based on preoperative SL: low lordosis (<15 degrees), moderate lordosis (15-25 degrees), and high lordosis (>25 degrees). Regression analyses were conducted to determine factors associated with postoperative SL and PDH. RESULTS Of the 171 patients included, 111 were in the static and 60 in the expandable cohorts. Patients with low preoperative lordosis experienced an increase in SL and maintained RL regardless of cage type. Those with moderate to high preoperative lordosis experienced a decrease in SL and RL with the static cage, but maintained SL and RL with the expandable cage. Although both cohorts showed an increase in PDH, the increase in the expandable cohort was greater. Preoperative SL was predictive of postoperative SL; preoperative SL, preoperative PDH, and cage type were predictive of postoperative PDH. CONCLUSION Expandable cages showed favorable results in restoring disc height and maintaining lordosis in the immediate postoperative period. Preoperative SL was the most significant predictor of postoperative SL. Thus, preoperative radiographic parameters and goals of surgery should be important considerations in surgical planning.

Study Design. Retrospective cohort. Objective. To describe our technique for and evaluate the time demand, radiation exposure and outcomes of skin-anchored intraoperative three-dimensional navigation (ION) in minimally invasive (MIS) lumbar surgery, and to compare these parameters to 2D fluoroscopy for MI-TLIF. Summary of Background Data. Limited visualization of anatomic landmarks and narrow access corridor in MIS procedures result in greater reliance on image guidance. Although two-dimensional fluoroscopy has historically been used, ION is gaining traction. Methods. Patients who underwent MIS lumbar microdiscectomy, laminectomy, or MI-TLIF using skin-anchored ION and MI-TLIF by the same surgeon using 2D fluoroscopy were selected. Operative variables, radiation exposure, and short-term outcomes of all procedures were summarized. Time-demand and radiation exposure of fluoroscopy and ION for MI-TLIF were compared. Results. Of the 326 patients included, 232 were in the ION cohort (92 microdiscectomies, 65 laminectomies, and 75 MI-TLIFs) and 94 in the MI-TLIF using 2D fluoroscopy cohort. Time for ION setup and image acquisition was a median of 22 to 24 minutes. Total fluoroscopy time was a median of 10 seconds for microdiscectomy, 9 for laminectomy, and 26 for MI-TLIF. Radiation dose was a median of 15.2 mGy for microdiscectomy, 16.6 for laminectomy, and 44.6 for MI-TLIF, of this, 93%, 95%, and 37% for microdiscectomy, laminectomy, and MI-TLIF, respectively were for ION image acquisition, with the rest attributable to the procedure. There were no wrong-level surgeries. Compared with fluoroscopy, ION for MI-TLIF resulted in lower operative times (92 vs. 108 min, P < 0.0001), fluoroscopy time (26 vs. 144 s, P < 0.0001), and radiation dose (44.6 vs. 63.1 mGy, P = 0.002), with equivalent time-demand and length of stay. ION lowered the radiation dose by 29% for patients and 55% for operating room personnel. Conclusion. Skin-anchored ION does not increase time-demand compared with fluoroscopy, is feasible, safe and accurate, and results in low radiation exposure. Level of Evidence: 3.

Study Design. Retrospective review of prospectively collected data. Objective. To investigate if zero profile devices offer an advantage over traditional plate/cage constructs for dysphagia rates in single level anterior cervical discectomy and fusion (ACDF). Summary of Background Data. Dysphagia rates following ACDF have been reported to be as high as 83%, most cases are self-limiting, but chronic dysphagia can continue in up to 35% of patients. Zero profile devices were developed to limit dysphagia, and other plate specific complications, however the literature is currently divided regarding their efficacy. Methods. Dysphagia was assessed by swallowing quality of life (SWAL-QOL) scores preoperatively, at 6 weeks and 12 weeks. Patient reported outcome measures (PROMs) including visual analog scale (VAS) and Neck Disability Index (NDI) were collected preoperatively, at 6 weeks and at 6 months. Univariate and multivariate regression analysis was conducted with SWAL-QOL score as the dependent variable. Results. Sixty-four patients were included, 41 received a zero profile device, and 23 received plate-graft construct. Both groups were similar regarding patient demographics, except operative time, with the zero-profile group having a shorter procedure time than the cage-plate group (44.88 ± 6.54 vs. 54.43 ± 14.71 min, P = 0.001). At all timepoints dysphagia rates were similar between the groups. Regression analysis confirmed preoperative SWAL-QOL and operative time were the only significant variables. PROMs were also similar between groups at all time points, except VAS neck at 6 months, which was lower in the plate-graft group (1.05 ± 1.48 vs. 3.43 ± 3.21, P = 0.007). Conclusion. Operative time and preoperative SWAL-QOL scores are predictive of dysphagia in single level ACDF. Zero profile devices had a significantly shorter operative time, and may provide a benefit in dysphagia rates in this regard. Level of Evidence: 3

Background: Minimally invasive transforaminal lumbar interbody fusion (MI-TLIF) has comparable fusion rates and outcomes to the open approach, though many surgeons avoid the technique due to an initial learning curve. No current studies have examined the learning curve of MI-TLIF with respect to fluoroscopy time and exposure. Our objective with this retrospective review was to therefore use a repeatable mathematical model to evaluate the learning curve of MI-TLIF with a focus on fluoroscopy time and exposure. Methods: We conducted a retrospective review of single level, primary fusions performed by a single surgeon during his initial experience with minimally invasive spine surgery. Chronologic case number was plotted against variables of interest, and learning was identified as the point at which the instantaneous rate of change of a curve fit to the data set equaled the average rate of change of the data set. Results: One hundred nine cases were reviewed. Proficiency in operative time was achieved at 38 cases with the first 38 requiring a median of 137 minutes compared to 104 minutes for the latter 71 cases (P , .0001). Mastery of fluoroscopy use occurred at case 51. The median fluoroscopy time for the first 51 cases was 2.8 minutes, which dropped to 2.1 minutes for cases 52 to 109 (P , .0001). The complication rate plateaued after 43 cases, with 3 of 11 total complications occurring in the latter 76 cases. Conclusions: Our results demonstrate the most gradual learning occurred with respect to fluoroscopy time and exposure, and operative time improved the quickest. Level of Evidence: IV. Clinical Relevance: These findings may guide spine surgeon education and training in minimally invasive techniques, and help determine safe case loads for radiation exposure during the initial learning phase of the technique. The model used to identify the learning curve can also be applied to several fields and surgical techniques.