Incidence and Etiology of Rare Saphenous Nerve Injury After Knee Surgery with Adductor Canal Block: A Retrospective Observational Study.

Background: Adductor canal block (ACB) is commonly included in multimodal analgesia regimens for knee surgery. Nonetheless, the incidence, etiology, and procedure-specific risk of saphenous nerve injury after knee surgery with ACB have not been established. Purpose: We sought to identify the risk of saphenous nerve injury during knee surgery with ACB. Methods: We conducted a retrospective cohort study of patients at a single institution who underwent elective knee surgery with ultrasound-guided ACB between January 1, 2014, and December 31, 2018, and had subsequent saphenous nerve injury. The primary outcome was the incidence of saphenous nerve injury within 3 months of surgery, by surgical type and approach. Secondary outcomes included attribution of the most likely etiology and clinical outcome of the injury. Results: In 28,196 cases of knee surgery with ACB, we identified 18 cases (0.06%) of saphenous nerve injury. The most common surgery associated with saphenous nerve injury was anterior cruciate ligament (ACL) reconstruction with autograft (8/18 cases); 3 cases of injury were seen after TKA, 2 after medial patellofemoral ligament reconstruction, 2 after arthroscopy/meniscal surgery, and 1 after patellar fixation. The most likely etiology of nerve injury was attributed to ACB in 5 of 18 cases (28%) and to non-ACB cause in 13 of 18 (72%). Prognosis was rated as unknown in 11 of 18, poor in 2 of 18, favorable in 3 of 18, and full recovery in 2 of 18. Conclusions: This 5-year retrospective, single-institution cohort study found a low overall incidence of saphenous nerve injury after knee surgery with ACB, but the injury likelihood varied based on surgery and approach. Although not statistically significant, ACL reconstruction with hamstring autograft and ACB performed for postoperative rescue analgesia were most frequently associated with nerve injury.

Abdominal aortic calcification is an independent predictor of perioperative blood loss in posterior spinal fusion surgery.

OBJECTIVE: Abdominal aortic calcification (AAC), often found incidentally on lateral lumbar radiographs, is increasingly recognized for its association with adverse outcomes in spine surgery. As a marker of advanced atherosclerosis affecting cardiovascular dynamics, this study evaluates AAC's impact on perioperative blood loss in posterior spinal fusion (PSF). METHODS: Patients undergoing PSF from March 2016 to July 2023 were included. Estimated blood loss (EBL) and total blood volume (TBV) were calculated. AAC was assessed on lateral lumbar radiographs according to the Kauppila classification. Predictors of the EBL-to-TBV ratio (%EBL/TBV) were examined via univariable and multivariable regression analyses, which adjusted for parameters such as hypertension and aspirin use. RESULTS: A total of 199 patients (47.2% female) were analyzed. AAC was present in 106 patients (53.3%). AAC independently predicted %EBL/TBV, accounting for an increase in blood loss of 4.46% of TBV (95% CI 1.17-7.74, p = 0.008). CONCLUSIONS: This is the first study to identify AAC as an independent predictor of perioperative blood loss in PSF. In addition to its link to degenerative spinal conditions and adverse postoperative outcomes, the relationship between AAC and increased blood loss warrants attention in patients undergoing PSF.

Spine surgery under neuraxial vs. general anesthesia: the current state of comparative outcomes research.

PURPOSE OF REVIEW: The impact of primary anesthetic technique on outcomes after spine surgery is controversial. Given frequent calls for well designed prospective comparative studies of neuraxial anesthesia vs. general anesthesia and recent reports of 'awake spine surgery' successes in the surgical literature, an updated evidence review is indicated. RECENT FINDINGS: Systematic reviews, population-based and retrospective cohort studies suggest few significant differences in important complications or global recovery between anesthetic techniques. On the basis of overall low-to-moderate quality evidence, neuraxial anesthesia is associated with statistically significant benefits for several individual outcomes compared with general anesthesia, including improved intraoperative hemodynamic stability, less postoperative nausea and vomiting, lower early pain scores and shorter length of hospital stay. There are ongoing calls for well designed, adequately powered prospective studies. SUMMARY: Our understanding of the risks, benefits and comparative outcomes between neuraxial anesthesia and general anesthesia for spine surgery is evolving. Although the results derived from this body of literature suggest specific benefits of neuraxial anesthesia, further research is required before widespread recommendations for either technique can be made. Until then, both neuraxial anesthesia and general anesthesia are reasonable choices for lumbar spine surgery of short duration, in appropriately selected patients.

Utility of Ultrasound-Guided Erector Spinae Plane Blocks for Postoperative Pain Management Following Thoracolumbar Spinal Fusion Surgery.

Purpose: The primary objective of this study is to determine if ultrasound-guided erector spinae plane blocks (ESPB) prior to thoracolumbar spinal fusion reduces opioid consumption in the first 24 hours postoperatively. Secondary objectives include ESPB effects on administration of opioids, utilization of intravenous patient-controlled analgesia (IV-PCA), pain scores, length of stay, and opioid related side effects. Methods: A retrospective cohort analysis was performed on consecutive, adult patients undergoing primary thoracolumbar fusion procedures. Demographic and baseline characteristics including diagnoses of chronic pain, anxiety, depression, and preoperative use of opioids were collected. Surgical data included surgical levels, opioid administration, and duration. Postoperative data included pain scores, opioid consumption, IV-PCA duration, opioid-related side effects, ESPB-related complications, and length of stay (LOS). Statistical analysis was performed using chi-squared and t-test analyses, multivariable analysis, and covariate adjustment with propensity score. Results: A total of 118 consecutive primary thoracolumbar fusions were identified between October 2019 and December 2021 (70 ESPB, 48 no-block [NB]). There were no significant demographic or surgical differences between groups. Median surgical time (262.50 mins vs 332.50 mins, p = 0.04), median intraoperative opioid consumption (8.11 OME vs 1.73 OME, p = 0.01), and median LOS (152.00 hrs vs 128.50 hrs, p = 0.01) were significantly reduced in the ESPB group. Using multivariable covariate adjustment with propensity score analysis only intraoperative opioid administration was found to be significantly less in the ESPB cohort. Conclusion: ESPB for thoracolumbar fusion can be performed safely in index cases. There was a reduction of intraoperative opioid administration in the ESPB group, however the care team was not blinded to the intervention. Extensive thoracolumbar spinal fusion surgery may require a different approach to regional anesthesia to be similarly effective as ESPB in isolated lumbar surgeries.

Comparative review of airway anesthesia and sedation methods for awake intubation.

PURPOSE OF REVIEW: Successful awake intubation hinges upon adequate airway anesthesia and sedation for patient comfort. This review will summarize relevant anatomy and regional anesthesia techniques to achieve airway anesthesia, and compare various airway anesthesia and sedation regimens. RECENT FINDINGS: Overall, nerve blocks consistently provided superior airway anesthesia, shorter time to intubation, higher patient comfort, and higher postintubation patient satisfaction. Additionally, ultrasound guidance can further provide benefit by reducing the amount of local anesthetic administered, leading to denser blockade, and proving invaluable in challenging clinical situations. Regarding sedation methods, numerous studies supported the use of dexmedetomidine, with or without the addition of supplemental sedation, such as midazolam, ketamine, or opioids. SUMMARY: Emerging evidence has indicated that nerve blocks for airway anesthesia may be superior to other methods of topicalization. Additionally, dexmedetomidine can be useful, both as monotherapy and with supplemental sedatives, to safely provide anxiolysis for the patient and increase success. However, it is crucial to note that the method of airway anesthesia and sedation regimen should be adapted to each patient and clinical situation, and knowledge of multiple techniques and sedation regimens can best equip anesthesiologists to do so.

Frailty Stratification Using the Modified 5-Item Frailty Index: Significant Variation within Frailty Patients in Spine Surgery.

BACKGROUND: Frailty status has been associated with higher rates of complications after spine surgery. However, frailty patients constitute a heterogeneous group based on the combinations of comorbidities. The objective of this study is to compare the combinations of variables that compose the modified 5-factor frailty index score (mFI-5) based on the number of comorbidities in terms of complications, reoperation, readmission, and mortality after spine surgery. METHODS: The American College of Surgeons - National Surgical Quality Improvement Program (ACS-NSQIP) Database from 2009-2019 was used to identify patients who underwent elective spine surgery. The mFI-5 item score was calculated and patients were classified according to number and combination of comorbidities. Multivariable analysis was used to assess the independent impact of each combination of comorbidities in the mFI-5 score on the risk of complications. RESULTS: A total of 167, 630 patients were included with a mean age of 59.9 ± 13.6 years. The risk of complications was the lowest in patients with diabetes + hypertension (OR = 1.2) and highest in those with the combination of congestive heart failure (CHF), diabetes, chronic obstructive pulmonary disease (COPD), and dependent status (OR = 6.6); there was a high variation in complication rate based on specific combinations. CONCLUSIONS: There is high variability in terms of relative risk of complications based on the number and combination of different comorbidities, especially with CHF and dependent status. Therefore, frailty status encompasses a heterogeneous group and sub-stratification of frailty status is necessary to identify patients with significantly higher risk of complications.

Continuous erector spinae plane catheters leading to unwanted neuraxial spread after spinal fusion surgery: a report of two cases from a terminated prospective randomized clinical trial.

BACKGROUND: Erector spinae plane blocks are used to improve outcomes after spine surgery, but pain frequently outlasts the duration of single injection blocks. We hypothesized continuous erector spinae plane (cESP) catheters would provide superior analgesia. We terminated a prospective double-blinded randomized clinical trial (RCT) comparing outcomes after multilevel spine surgery among patients randomized to saline versus ropivacaine cESP catheters. We present two cases of undesired epidural spread of ropivacaine and discuss etiology, management, and future research directions. CASE PRESENTATION: Nine out of 44 patients (planned) enrolled in the RCT; 6/9 were randomized to receive ropivacaine infusions via bilateral cESP catheters. Two patients underwent uncomplicated posterior lumbar fusion and were recovering well with minimal pain and opioid requirements through postoperative day 1. Both had new-onset urinary retention and bilateral lower extremity numbness, weakness and paresthesias (24 and 30 hours after infusion-start time, respectively). One patient underwent MRI, which was remarkable for an epidural fluid collection compressing the thecal sac. Infusions were stopped, cESP catheters were removed and symptoms fully resolved over the next 3-5 hours. CONCLUSIONS: Unwanted neuraxial spread of local anesthetic from cESP catheters may be a unique consideration after spine surgery, accounted for by unpredictable local anesthetic distribution within disrupted surgical planes. Future studies are indicated to determine optimal catheter regimens together with guidance for extended monitoring in parallel with further studies of efficacy in spine surgery cohorts. TRIAL REGISTRATION NUMBER: NCT05494125.

Up to 10-year surveillance comparison of survivability in single-level cervical disc replacement versus anterior cervical discectomy and fusion in New York.

OBJECTIVE: Cervical disc replacement (CDR) is an alternative treatment to anterior cervical discectomy and fusion (ACDF), which is the current gold standard, for degenerative cervical diseases such as cervical spondylotic myelopathy and cervical radiculopathy. CDR has several theoretical benefits over ACDF, including preservation of motion, earlier return to unrestricted activity, and potentially a lower risk of adjacent-segment disease. Recent literature has reported positive clinical results for CDR, but few studies have investigated the long-term risk of revision surgery of CDR versus ACDF. The purpose of this study was to identify and analyze the epidemiological, clinical, and operative risk factors that affect revision rates following single-level CDR and ACDF procedures. METHODS: A retrospective cohort was extracted from the Statewide Planning and Research Cooperative System using ICD-9 and CPT codes. Inclusion criteria were adult patients undergoing primary, subaxial (C3-7), single-level ACDF or CDR for cervical radiculopathy and/or cervical spondylotic myelopathy between 2005 and 2013. Survivability was defined as the time between the index procedure and the presence of a subsequent discharge record for cervical spinal fusion or disc replacement. Statistical analyses were performed using chi-square tests, t-tests, Cox proportional hazards models, and a Kaplan-Meier plot. RESULTS: A total of 7450 patients were included in this study (6615 ACDF and 835 CDR). When adjusted for patient demographics, the hazard ratios showed no significant differences in the incidence of revision risk between the two cohorts. The CDR cohort had a higher incidence of postoperative dysphagia (p < 0.05). Patients undergoing ACDF had a longer average hospital stay (2.8 vs 1.9 days, p < 0.001). There was no significant difference in time to revision surgery (p = 0.486). CONCLUSIONS: CDR and ACDF have both been shown to be effective treatments for cervical spine disease. CDR patients had a shorter average inpatient hospital stay compared with ACDF patients but tended to experience dysphagia more frequently. There was a tendency toward increased survivability of CDR; however, this was not found to be statistically significant at any time point. The large size and heterogeneity of each cohort and the availability of > 10 years of surveillance data differentiate this study from other published literature. This investigation has limitations inherent to large data analysis studies, including the implementation and inaccuracy of diagnosis and procedural coding; however, this reflects real-world use of coding by practitioners.

Association of Frailty and Preoperative Hypoalbuminemia with the Risk of Complications, Readmission, and Mortality After Spine Surgery.

BACKGROUND: Frailty status and hypoalbuminemia have been associated with higher rates of complications after spine surgery. However, the combination of both conditions has not been fully analyzed. The objective of this study was to assess the effect of frailty and hypoalbuminemia on the risk of complications after spine surgery. METHODS: The American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) database from 2009 to 2019 was used. Frailty status was calculated using the modified 5-item frailty index (mFI-5). Patients were classified into nonfrail (mFI = 0), pre-frail (mFI = 1), and frail (mFI ≥2) groups and also based on albumin levels into normal (≥3.5 g/dL) and hypoalbuminemia groups (<3.5 g/dL). The latter group was also subclassified into mild and severe hypoalbuminemia groups. Multivariable analysis was used. A Spearman ρ correlation between albuminemia and mFI-5 was also performed. RESULTS: A total of 69,519 patients (36,705 men [52.8%] and 32,814 women [47.2%]) with a mean age of 61.0 ± 13.2 years were included. Patients were classified as nonfrail (n = 24,897), pre-frail (n = 28,897), and frail groups (n = 15,725). Hypoalbuminemia was significantly higher in the frail group (11.4%) compared with the nonfrail group (4.3%). An inverse correlation was observed between albumin levels and frailty status (ρ = -0.139; P < 0.0001). Frail patients with severe hypoalbuminemia had significantly higher risk of complications (odds ratio [OR], 5.0), reoperation (OR, 3.3), readmission (OR, 3.1), and mortality (OR, 31.8) compared with patients without hypoalbuminemia. CONCLUSIONS: The combination of frailty and hypoalbuminemia significantly increases the risk of complications after spine surgery. The prevalence of hypoalbuminemia in the frailty group was significantly higher than in nonfrail patients (11.4% vs. 4.3%). Both conditions should be evaluated preoperatively.

Comparative effectiveness of anesthetic technique on outcomes after lumbar spine surgery: a retrospective propensity score-matched analysis of the National Surgical Quality Improvement Program, 2009-2019.

BACKGROUND: The impact of anesthetic technique on spine surgery outcomes is controversial. Using a large national sample of patients, we compared outcomes after lumbar decompression under regional anesthesia (RA: spinal or epidural) or general anesthesia (GA). METHODS: A retrospective population-based study of American College of Surgeons National Surgical Quality Improvement Program data (2009-2019). Patients were propensity score (PS) matched 3:1 (GA:RA) on demographic and surgical variables. The primary outcome was the association between anesthetic type and any complication (cardiac, pulmonary, renal, transfusion, stroke, infectious, deep vein thrombosis/pulmonary embolus). Secondary outcomes included the association between anesthetic type and individual complications, readmission and length of stay (LOS). Unadjusted comparisons (OR, 95% CI), logistic regression and adjusted generalized linear modeling (parameter estimate, PE, 95% CI) were performed before and after PS matching. RESULTS: Of 1 51 010 cases, 149 996 (99.3%) were performed under GA, and 1014 (0.67%) under RA. After matching, 3042 patients with GA were compared with 1014 patients with RA. On unadjusted analyses, RA was associated with lower odds of complications (OR 0.43, 0.3 to 0.6, p<0.001), shorter LOS (RA: 1.1±3.8 days vs GA: 1.3±3.0 days; p<0.001) and fewer blood transfusions (RA: 3/1014, 0.3% vs GA: 40/3042, 1.3%; p=0.004). In adjusted analyses, RA was associated with fewer complications (PE -0.43, -0.81 to -0.06, p=0.02) and shorter LOS (PE -0.76, -0.90 to -0.63, p<0.001). There was no significant association between anesthetic type and readmission (PE -0.34, -0.74 to 0.05, p=0.09). CONCLUSIONS: Compared with GA, RA was associated with fewer complications, less blood transfusion and shorter LOS after spine surgery. Although statistically significant, the magnitude of effects was small and requires further prospective study.

Effectiveness of oral versus intravenous tranexamic acid in primary total hip and knee arthroplasty: a randomised, non-inferiority trial.

BACKGROUND: Tranexamic acid (TXA) reduces rates of blood transfusion for total hip arthroplasty (THA) and total knee arthroplasty (TKA). Although the use of oral TXA rather than intravenous (i.v.) TXA might improve safety and reduce cost, it is not clear whether oral administration is as effective. METHODS: This noninferiority trial randomly assigned consecutive patients undergoing primary THA or TKA under neuraxial anaesthesia to either one preoperative dose of oral TXA or one preoperative dose of i.v. TXA. The primary outcome was calculated blood loss on postoperative day 1. Secondary outcomes were transfusions and complications within 30 days of surgery. RESULTS: Four hundred participants were randomised (200 THA and 200 TKA). The final analysis included 196 THA patients (98 oral, 98 i.v.) and 191 TKA patients (93 oral, 98 i.v.). Oral TXA was non-inferior to i.v. TXA in terms of calculated blood loss for both THA (effect size=-18.2 ml; 95% confidence interval [CI], -113 to 76.3; P<0.001) and TKA (effect size=-79.7 ml; 95% CI, -178.9 to 19.6; P<0.001). One patient in the i.v. TXA group received a postoperative transfusion. Complication rates were similar between the two groups (5/191 [2.6%] oral vs 5/196 [2.6%] i.v.; P=1.00). CONCLUSIONS: Oral TXA can be administered in the preoperative setting before THA or TKA and performs similarly to i.v. TXA with respect to blood loss and transfusion rates. Switching from i.v. to oral TXA in this setting has the potential to improve patient safety and decrease costs.

Intraoperative Methadone and Short Stay Spine Surgery: Possible Barriers to Implementation and Future Opportunities.

The frequency of shorter stay spine surgery is increasing. Acute pain is a common barrier to discharge following spine surgery. Long-acting opioid medications like methadone have the potential to provide sustained analgesia when given intraoperatively. Methadone has been effectively used in complex spine surgery, cardiac surgery, and more recently applied to ambulatory procedures. In this article, we summarize the pertinent available literature on the use of intraoperative methadone for spine surgery as well as the recent data on intraoperative methadone for ambulatory surgery. The aim of this perspectives article is to describe the potential opportunities for applying intraoperative methadone to shorter stay spine surgery as well as barriers to more widespread use. While there are currently no trials that have specifically studied methadone for shorter stay spine surgery specifically to date, it is a promising area for future research.

Ultrasound-guided fascial plane blocks for spine surgery.

PURPOSE OF REVIEW: The development of truncal and fascial plane blocks has created novel opportunities to apply regional analgesic techniques to patients undergoing spine surgery. This review will summarize recent literature devoted to evaluating candidate blocks for spine surgery, including erector spinae plane block, thoracolumbar interfascial plane block, midpoint transverse process to pleura block, and transversus abdominis plane block. Procedure-specific effects of blocks on patient and healthcare system outcomes will be presented and gaps in care and knowledge will be highlighted. RECENT FINDINGS: The most studied paradigm was bilateral erector spinae plane block for lumbar spine surgery. The most common outcomes assessed were early postoperative pain scores, opioid consumption and related side effects, and length of hospital stay. All candidate blocks were associated with mixed evidence for analgesic and opioid-sparing benefits, and/or reductions in length of hospital stay. The magnitude of these effects was overall small, with many studies showing statistically but not clinically significant differences on outcomes of interest. This may reflect, at least in part, the current state of the (emerging) evidence base on this topic. SUMMARY: Our understanding of the risks, benefits, and value of truncal and fascial plane blocks for spine surgery cohorts is evolving. Although the results derived from this body of literature are encouraging, further research is required before the widespread adoption of specified blocks into spine care can be recommended.

Surgeon-Placed Erector Spinae Plane Catheters for Multilevel Lumbar Spine Fusion: Technique and Outcomes Compared With Single-Shot Blocks.

BACKGROUND: Postoperative pain management of multilevel lumbar fusion remains challenging. There are few reports of opioid-sparing regional analgesia for spine surgery. We present a novel method for surgeon-placed erector spinae plane (ESP) catheters for multilevel lumbar spine fusion and compare pain- and opioid-related outcomes in a matched cohort who received anesthesiologist-placed ESP blocks. METHODS: A retrospective matched pilot study of 18 patients: 6 received intraoperative, bilateral ESP catheters. Tunneled catheters were placed under the intact ESP at the proximal end of the incision. Continuous infusions of ropivacaine (0.2%) were started in the postanesthesia care unit (PACU) after emergence from anesthesia and maintained for 48 hours. Catheter patients were matched 1:2 with 12 patients who received preincision single-shot ESP blocks administered by an anesthesiologist, according to age, gender, American Society of Anesthesiologists class, body mass index, and number of spinal levels fused. All patients were provided opioid intravenous patient-controlled analgesia (IV-PCA). Numeric rating scale pain scores (NRS, 0-10), length of stay (LOS), opioid consumption (oral morphine equivalents, mg), opioid side effects, and complications (motor weakness, local anesthetic toxicity, infection, technical issues, and failure), were compared in the PACU and on the nursing floor. RESULTS: Only 1/6 patients with ESP catheter used opioid IV-PCA, compared with 11/12 who received ESP blocks. There were no differences in total opioid consumption (catheters: 135 ± 141 mg; blocks: 183 ± 112 mg; P = 0.448) or median (interquartile range) LOS (catheters: 73 [50,107] hours; blocks: 90 [72,116] hours, P = 0.708). NRS pain was significantly higher in the PACU after ESP catheters (5.9 ± 1.7) vs ESP blocks (3.3 ± 2.4; P = 0.036), but no differences were found at later timepoints (5.0 ± 1.6 vs 4.3 ± 1.1, respectively; P = 0.383). No catheter-related complications were found. CONCLUSION: Surgeon-placed ESP catheters represent a simple technique to provide regional analgesia, particularly in centers lacking regional anesthesiology services. Risks, benefits, and efficacy compared to other techniques require prospective study.

Longitudinal Trends of Patient Demographics and Morbidity of Different Approaches in Lumbar Interbody Fusion: An Analysis Using the American College of Surgeons National Surgical Quality Improvement Program Database.

OBJECTIVE: The aims of this study were to determine the time trend of demographics, complications, and outcomes for patients undergoing posterior lumbar interbody fusion/transforaminal lumbar interbody fusion (PLIF/TLIF) or anterior lumbar interbody fusion/lateral lumbar interbody fusion (ALIF/LLIF) and to compare the differences in the time trends between both procedures. METHODS: The American College of Surgeons National Surgical Quality Improvement Program database was queried for patients undergoing PLIF/TLIF and ALIF/LLIF procedures. Outcomes were analyzed for differences between 2 time periods in the PLIF/TLIF and ALIF/LLIF cohorts separately (2009-2013 and 2015-2019). Longitudinal time trends of the 2 procedures were determined by difference-in-differences (DID) analysis. Statistical significance was defined as P < 0.05. RESULTS: For both approaches, there was an increase in age and American Society of Anesthesiologists class over time, accompanied by a significant decrease in blood transfusions and morbidity. The DID analysis showed a greater change in age (DID:-1.8%; P < 0.001), and more patients were rated American Society of Anesthesiologists class 3 (DID: -2.4%; P = 0.033) in the ALIF/LLIF cohort than in the PLIF/TLIF cohort. Length of stay declined significantly over time in both cohorts, with a greater reduction observed for patients who underwent ALIF/LLIF than for patients who underwent PLIF/TLIF (DID: 0.2%; P = 0.014). There were no changes in readmission rates over time in either cohort (PLIF/TLIF DID: 0.6%; P = 0.080; ALIF/LLIF DID: -0.2%; P = 0.696). CONCLUSIONS: Time trends for PLIF/TLIF and ALIF/LIIF showed a significant increase in the number of older patients with complex medical status undergoing surgery. Despite these trends, there were decreases in overall postoperative morbidity, incidence of blood transfusion, and length of stay, without increasing readmission. These results suggest general improvement in surgical and perioperative management of lumbar fusion over time with greater gains found in ALIF/LLIF-specific care than in PLIF/TLIF.