Clinical outcomes and complications after biportal endoscopic spine surgery: a comprehensive systematic review and meta-analysis of 3673 cases
PURPOSE/OBJECTIVE:Current literature suggests that biportal spinal endoscopy is safe and effective in treating lumbar spine pathology such as lumbar disc herniation, lumbar stenosis, and degenerative spondylolisthesis. No prior study has investigated the postoperative outcomes or complication profile of the technique as a whole. This study serves as the first comprehensive systematic review and meta-analysis of biportal spinal endoscopy in the lumbar spine. METHODS:A PubMed literature search provided over 100 studies. 42 papers were reviewed and 3673 cases were identified with average follow-up time of 12.5 months. Preoperative diagnoses consisted of acute disc herniation (1098), lumbar stenosis (2432), and degenerative spondylolisthesis (229). Demographics, operative details, complications, and perioperative outcome and satisfaction scores were analyzed. RESULTS:Average age was 61.32 years, 48% male. 2402 decompressions, 1056 discectomies, and 261 transforaminal lumbar Interbody fusions (TLIFs) were performed. Surgery was performed on 4376 lumbar levels, with L4-5 being most common(61.3%). 290 total complications occurred, 2.23% durotomies, 1.29% inadequate decompressions, 3.79% epidural hematomas, and < 1% transient nerve root injuries, infections, and iatrogenic instability. Significant improvement in VAS-Back, VAS-Leg, ODI, and Macnab Scores were seen across the cohort. CONCLUSION/CONCLUSIONS:Biportal spinal endoscopy is a novel method to address pathology in the lumbar spine with direct visualization through an endoscopic approach. Complications are comparable to previously published rates. Clinical outcomes demonstrate effectiveness. Prospective studies are required to assess the efficacy of the technique as compared to traditional techniques. This study demonstrates that the technique can be successful in the lumbar spine.
78. Increased risk of postoperative L5 nerve root palsy with ALIF compared to TLIF [Meeting Abstract]
BACKGROUND CONTEXT: L5 nerve root palsy is a complication that can occur after ALIF indirect decompression. It is thought to occur due to the dimensional change in the L5 foramen that can either compress or cause a stretch neuropraxia of the nerve root. While this complication has been observed, reports and studies highlighting its incidence and risk are lacking. PURPOSE: To determine whether ALIF leads to an increased risk in L5 palsy, we sought to compare the relative risk compared to TLIF. We hypothesize that since foraminotomy is part of the TLIF procedure, it should demonstrate a difference in nerve root palsy compared to ALIF indirect decompression. STUDY DESIGN/SETTING: A single institution retrospective cohort study. PATIENT SAMPLE: A total of 626 patients (262 ALIF, 179 open TLIF, 185 MIS TLIF). The study period was 2017 to 2021. OUTCOME MEASURES: Primary outcomes were postoperative leg pain, sensory deficits, and motor weakness in tibialis anterior (TA), extensor hallucis longus (EHL) and gastrocnemius (GC). Secondary outcomes were infection, return to operating room (OR), and return to emergency center (EC) within 90 days.
METHOD(S): Retrospective comparative cohort study comparing ALIF vs TLIF. Inclusion criteria were all patients who underwent L5-S1 ALIF or L5-S1 TLIF (both open and MIS). Multilevel surgeries were excluded. The rate of postop nerve palsy was compared for the two treatment approaches. Chi-square was performed for all categorical comparisons and ANOVA was performed for continuous statistical comparisons.
RESULT(S): There were subtle differences in baseline characteristics between groups. ALIF patients were younger (p = 0.016), had less BMI (p = 0.026) and less likely to smoke (p = 0.008). There were no differences in gender or diabetes status. Patients undergoing TLIF (open and MIS) were more likely to be operated for lumbar spinal stenosis and radiculopathy (p < 0.001). There was an overall 3% rate of neuro deficits in the study population with a higher rate in those undergoing ALIF (5.3%) compared with open TLIF (0.6%) and MIS TLIF (2.2%) (p = 0.011). There was a rate of 3.1% EHL palsy in the ALIF group which was higher than TLIF (both open and MIS) (p = 0.048). There was a trend towards higher TA and GC nerve deficits in the ALIF group, but the difference was not significant. Additionally, there was a trend towards higher rates of return to OR for nerve deficit in the ALIF group, but this was not significant. However, ALIF patients had higher return to OR in 90 days for any reason (p = 0.01). There were no further differences between the groups. Among the 14 ALIF patients with any nerve deficit, 7 followed up at 3 mos and 5 in 1 year. At 3 mos, 5 of 7 patients had improvement in their nerve deficit and at 1 year, 5 of 5 patients had improved their deficiency.
CONCLUSION(S): This study demonstrates a higher rate of L5 nerve root palsy with ALIF compared to TLIF as evidenced by higher rates of EHL palsy with a rate of 3.1% in our study population. The study, however, is limited by its retrospective nature and subtle differences noted in demographics. Despite these differences, ALIF patient characteristics tended to be more favorable, which are unlikely to confound results of higher postoperative nerve deficits. Further study will be required to understand the mechanisms and radiological risk factors for postoperative L5 palsy after ALIF. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs.
Assessing Postoperative Pseudarthrosis in Anterior Cervical Discectomy and Fusion (ACDF) on Dynamic Radiographs Using Novel Angular Measurements
STUDY DESIGN/METHODS:A retrospective review of operative patients at a single institution. OBJECTIVE:To validate a novel method of detecting pseudarthrosis on dynamic radiographs. SUMMARY OF BACKGROUND DATA/BACKGROUND:A common complication after anterior cervical discectomy and fusion is pseudarthrosis. A previously published method for detecting pseudarthrosis identifies a 1Â mm difference in interspinous motion (ISM), which requires calibration of images and relies on anatomic landmarks difficult to visualize. An alternative is to use angles between spinous processes, which does not require calibration and relies on more visible landmarks. METHODS:ISM was measured on dynamic radiographs using the previously published linear method and new angular method. Angles were defined by lines from screw heads to dorsal points of spinous processes. Angular cutoff for fusion was calculated using a regression equation correlating linear and angular measures, based on the 1Â mm linear cutoff. Pseudarthrosis was assessed with both cutoffs. Sensitivity, specificity, inter- and intra-reliability of angular and linear measures used post-operative CT as the reference. RESULTS:242 fused levels (81 allograft, 84 PEEK, 40 titanium, 37 standalone cages) were measured in 143 patients (mean age 52.0Â±11.5, 42%F). 36 patients (66 levels) had 1-year postoperative CTs; 13 patients (13 levels) had confirmed pseudarthrosis. Linear and angular measurements closely correlated (R=0.872), with 2.3Â° corresponding to 1Â mm linear ISM. Potential pseudarthroses was found in 28.0% and 18.5% levels using linear and angular cutoffs, respectively. Linear cutoff had 85% sensitivity, 87% specificity; angular cutoff had 85% sensitivity, 96% specificity for detecting CT-validated pseudarthrosis. Interclass correlation coefficients were 0.974 and 0.986 (both P<0.001); intra-rater reliability averaged 0.953 and 0.974 (P<0.001 for all) for linear and angular methods, respectively. CONCLUSIONS:The angular measure for assessing potential pseudarthrosis is as sensitive as and more specific than published linear methods, has high inter-observer reliability, and can be used without image calibration.
Bone Graft Options in Spinal Fusion: A Review of Current Options and the Use of Mesenchymal Cellular Bone Matrices
BACKGROUND:Spinal fusion is the mainstay treatment for various spinal conditions ranging from lumbar and cervical stenosis to degenerative spondylolisthesis as well as extensive deformity corrections. A new emerging category of allograft is cellular bone matrices (CBMs), which take allogeneic mesenchymal stem cells and incorporate them into an osteoconductive and osteoinductive matrix. This study reviewed the current spinal fusion options and new emerging treatment options. METHODS:Articles were searched using PubMed. The search included English publications since January 1, 2014, using the search terms "cellular bone matrix," "mesenchymal stem cells spinal fusion," "spinal arthrodesis AND mesenchymal stem cells," and "spine fusion AND cellular bone matrix." RESULTS:Spinal fusion is accomplished through the use of allografts, autografts, and bone graft substitutes in combination or alone. An emerging category of allograft is CBMs, in which an osteoconductive and osteoinductive matrix is filled with mesenchymal stem cells. Studies demonstrate that CBMs have achieved equivalent or better fusion rates compared with traditional options for anterior cervical discectomy and fusions and posterolateral lumbar fusions; however, the studies have been retrospective and lacking control groups and therefore not ideal. CONCLUSIONS:Many treatment options have been successfully used in spinal fusion. Newer allografts such as CBMs have shown promising results in both animal and clinical studies. Further research is needed to determine the therapeutic dose of mesenchymal stem cells delivered within CBMs.
Fusing to the Sacrum/Pelvis: Does the Risk of Reoperation in Thoracolumbar Fusions Depend on Upper Instrumented Vertebrae (UIV) Selection?
BACKGROUND:There is controversy as to whether fusions should have the upper instrumented vertebrae (UIV) end in the upper lumbar spine or cross the thoracolumbar junction. This study compares outcomes and reoperation rates for thoracolumbar fusions to the sacrum or pelvis with UIV in the lower thoracic versus lumbar spine to determine if there is an increased reoperation rate depending on UIV selection. METHODS:A retrospective review of prospectively collected data was conducted from a single-center database on adult patients with degeneration and deformity who underwent primary and revision fusions with a caudal level of S1 or ilium between 2012 and 2018. Fusions were classified as anterior, posterior, or combination approach. Revision fusions included patients who had spinal surgery at another institution prior to their revision surgery at the center. Patients were categorized into 1 of 3 groups based on UIV: T9-T11, upper lumbar region (L1-L2), and lower lumbar region (L3-L5). Inclusion criteria were age 18 years or older and at least 1 year of clinical follow-up. Patients were excluded from analysis if they had tumors, infections, or less than 1 year of follow-up after the index procedure. RESULTS:= .002) from the reoperation rates for the same diagnoses in the upper lumbar spine (4.6% and 1%) or lower lumbar spine (6.2% and 0%). A multivariate logistical regression model at 2-year follow up did not show a statistically significant difference between reoperation rates between the thoracic and upper lumbar spine UIV groups. CONCLUSION/CONCLUSIONS:Constructs with UIV in the thoracic spine suffer from higher rates of proximal junctional kyphosis and pseudoarthrosis, whereas those with UIV in the upper lumbar spine have higher rates of adjacent segment disease. Given this tradeoff, there is no certain recommendation on what UIV will result in a lower reoperation rate in thoracolumbar fusion constructs to the sacrum or pelvis. Surgeons must evaluate patient characteristics and risks to make the optimal decision.
Patient Outcomes After Single-level Coflex Interspinous Implants Versus Single-level Laminectomy
STUDY DESIGN/METHODS:Retrospective cohort analysis. OBJECTIVE:The aim of this study was to compare postoperative outcomes of Coflex interspinous device versus laminectomy. SUMMARY OF BACKGROUND DATA/BACKGROUND:Coflex Interlaminar Stabilization device (CID) is indicated for one- or two-level lumbar stenosis with grade 1 stable spondylolisthesis in adult patients, as an alternative to laminectomy, or laminectomy and fusion. CID provides stability against progressive spondylolisthesis, retains motion, and prevents further disc space collapse. METHODS:Patients â‰¥18 years' old with lumbar stenosis and grade 1 stable spondylolisthesis who underwent either primary single-level decompression and implantation of CID, or single-level laminectomy alone were included with a minimum 90-day follow-up at a single academic institution. Clinical characteristics, perioperative outcomes, and postoperative complications were reviewed until the latest follow-up. Ï‡2 and independent samples t tests were used for analysis. RESULTS:Eighty-three patients (2007-2019) were included: 37 cases of single-level laminectomy (48.6% female) were compared to 46 single-level CID (50% female). CID cohort was older (CID 69.0â€ŠÂ±â€Š9.4 vs. laminectomy 64.2â€ŠÂ±â€Š11.0, Pâ€Š=â€Š0.042) and had higher American Society of Anesthesiologists (ASA) grade (CID 2.59â€ŠÂ±â€Š0.73 vs. laminectomy 2.17â€ŠÂ±â€Š0.48, Pâ€Š=â€Š0.020). CID patients had higher estimated blood loss (EBL) (97.50â€ŠÂ±â€Š77.76 vs. 52.84â€ŠÂ±â€Š50.63â€ŠmL, Pâ€Š=â€Š0.004), longer operative time (141.91â€ŠÂ±â€Š47.88 vs. 106.81â€ŠÂ±â€Š41.30â€Šminutes, Pâ€Š=â€Š0.001), and longer length of stay (2.0â€ŠÂ±â€Š1.5 vs. 1.1â€ŠÂ±â€Š1.0â€Šdays, Pâ€Š=â€Š0.001). Total perioperative complications (21.7% vs. 5.4%, Pâ€Š=â€Š0.035) and instrumentation-related complication was higher in CID (10.9% vs. 0% laminectomy group, Pâ€Š=â€Š0.039). There were no other significant differences between the groups in demographics or outcomes. CONCLUSION/CONCLUSIONS:Single-level CID devices had higher perioperative 90-day complications, longer operative time, length of stay, higher EBL compared to laminectomies alone. Similar overall revision and neurologic complication rates were noted compared to laminectomy at last follow-up.Level of Evidence: 3.
Anterior Approach to the Subaxial Cervical Spine: Pearls and Pitfalls
Since its introduction by Smith and Robinson, the anterior approach to the subaxial cervical spine has become one of the standard procedures for numerous cervical spine pathologies, including, but not limited to degenerative disease, trauma, tumor, deformity, and instability. Along with its increasing popularity and improvements in anterior instrumentation techniques, a comprehensive knowledge of the surgical anatomy during the anterior exposure is critical for trainees and experienced spine surgeons alike to minimize the infrequent but potentially devastating risks associated with this approach. Understanding the anatomy and techniques to minimize damage to relevant structures can reduce the risks of developing notable postoperative complications and morbidity.
Lumbar Endoscopic Spine Surgery A Comprehensive Review
Endoscopic spine surgery (ESS) is growing in popularity as a minimally invasive approach to a variety of spinal conditions. Similar to other types of minimally invasive spine surgery (MISS), ESS aims to address the underlying pathology while minimizing surrounding tissue disruption. Its use in the lumbar spine has progressed over the past 50 years and is now routinely used in cases of lumbar disc herniations and stenosis. This review defines common terminology, highlights important developments in the history of ESS, and discusses its current and future application in the lumbar spine.
P138. Crossing the junction: effect of fusion length on reoperations for revision thoracolumbar fusion to sacrum [Meeting Abstract]
BACKGROUND CONTEXT: The thoracolumbar junction poses increased risk for high stress on upper lumbar discs when not adequately fused. However, controversy persists. This study evaluates outcomes of upper instrumented vertebrae (UIV) selection in the thoracic versus the upper lumbar spine when fusing to the sacrum. PURPOSE: To compare revision rates for thoracolumbar fusions to the sacrum and pelvis at 1- and 2-year follow-up, stratified by UIV selection. STUDY DESIGN/SETTING: Retrospective cohort study at a single institution. PATIENT SAMPLE: A total of 968 patients who had thoracolumbar fusion surgery between 2012-2018 with at least one year of postoperative follow-up. OUTCOME MEASURES: Reoperation rates from 1 and 2 years after revision surgery, reoperation diagnoses, body mass index (BMI), gender, Charleston Comorbidity Index (CCI), perioperative complications, ASA grade (ASA), operative time (OT), and blood loss (EBL).
METHOD(S): A retrospective review of patients undergoing revision spinal fusion with lower instrumented vertebra of S1 or pelvis between 2012-2018 at a single institution was performed. Patients with less than 1 year of follow-up after their index procedure were excluded from the analysis. Patients were categorized based on UIV into 6 groups: T9-T11, L1, L2, L3, L4, and L5. Demographic and operative data were collected and compared between the different UIV groups in each cohort using chi-squared and ANOVA tests. Revision rates at 1- and 2-year follow-up and the reasons for revision were compared between groups.
RESULT(S): There were 168 revision spinal fusions that reached 1-year follow-up, with 54 having UIV at T9-T11, 2 fusions L1 to sacrum, 26 fusions L2 to sacrum, 25 fusions L3 to sacrum, 36 fusions L4 to sacrum, 23 fusions L5 to sacrum. There was significant difference in patient age, with oldest in the L1 group (65.5+/-3.5) and youngest in the L5 group (51+/-15.4 p<0.001). There was significant difference in gender as both cases in L2 was female and L5 fusions only had 39.1% females (p = 0.006). There were no differences in BMI, CCI, and ASA. EBL (1891.6mL+/-1226.9mL p <0.001) and length of stay (7.7+/-3.0 p <0.001) was highest in the T9-11 UIV group. Operative time was highest in the L1 (464.5+/-174.7 p<0.001) UIV group. Levels added on top of prior fusion were calculated by subtracting UIV of index fusion to past UIV. Adding on 2 levels had a 1-year revision rate of 14.3% (p = 0.032), while adding on 1 level had a 0% 1-year revision rate. Adding on 4 levels had a revision rate of 12.5%, and adding on 7 levels had a 50% 1-year revision rate. At 2 years, adding on 1 level had revision rate of 25% and adding on 2 levels had a revision rate of 20% (p = 0.769). There is no statistically significant difference in perioperative complication rates between UIV groups (p = 0.114). The reoperation rate at 1 year for all levels was 9% and highest in UIV at L1 (50%, p=0.06). At 2-year follow-up, the reoperation rate for the total cohort was 32.34% with the highest revision rate for fusion from L2 to sacrum (53.85%) followed by (T9-T11 sacrum fusion 42.31%, L4 to sacrum31.71%, L3 to sacrum 30%, L5 to sacrum 25.04%, L1 to sacrum 25%, p=0.195). Grouping the UIV into lower thoracic (T9-T11), upper lumbar (L2-L3), and lower lumbar (L4-L5) showed similar revision rates at one year (p=0.697). At two years, lower thoracic group had a revision rate of 40% versus, 23.3% in the upper lumbar group (p =0.399).
CONCLUSION(S): There is no statistically significant difference in reoperation rates for revision thoracolumbar fusions to the sacrum/pelvis associated with different UIV selection. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs.
123. Residual foraminal stenosis and increasing levels decompressed are risk factors for postoperative C5 palsy [Meeting Abstract]
BACKGROUND CONTEXT: C5 palsy stands as a known but poorly understood complication of cervical spine surgery with rates reported as high as 30%. Although there are multiple studies presenting different risk factors, variability in findings have led to controversy in the etiology of postoperative C5 palsy. PURPOSE: To evaluate factors that predispose a patient to developing C5 palsy following cervical spine surgery. STUDY DESIGN/SETTING: Retrospective review of a large single center academic institution. PATIENT SAMPLE: This study included 239 cervical spinal procedures from 2013 to 2018. OUTCOME MEASURES: Patient demographics, surgical procedure and approach, perioperative clinical characteristics, postoperative rate of C5 palsy, C5 palsy resolution, and radiographic outcomes.
METHOD(S): Patients >=18 years of age who underwent cervical spinal surgery including the C4/C5 level, with minimum 1-year follow-up were included. C5 palsy was defined as deltoid +/- bicep weakness with Modified Rankin Scale grading at least 1 point below baseline (BL). Characteristics studied include: demographics, surgical procedure and approach (decompression and/or fusion). Radiographic analyses of MRI and CT measurements of foramen dimensions and spinal cord drift at BL and follow-up were performed. Statistical analyses included t-tests, chi-square analysis, and multivariate logistic regression to determine independent predictive factors. A receiver operating characteristic curve was run to determine the cutoff levels for predictive factors. Significance set at p<0.05.
RESULT(S): A total of 239 patients were included, with a C5 palsy rate of 6.3% for all cases. Subjects that developed C5 palsy were older (64.67+/-8.61 vs 57.56+/-11.61, p=0.021), had more levels decompressed posteriorly (3.20+/-1.82 vs 1.12+/-1.74, p<0.001), a higher rate of preoperative myelomalacia (60% vs 19.6%, p=0.008), and higher CCI (3.80+/-1.97 vs 2.35+/-1.95, p=0.005). Anterior cervical discectomy and fusion (ACDF) surgeries had a 2.4% rate of C5 palsy while the posterior approach rate was 11.9% (p<0.007). The highest rate was in laminectomy and posterior fusion at 15.2% (p<0.001). There were no significant differences in palsy resolution between those treated surgically compared to those not treated. Radiographically, C5 palsy patients had smaller postoperative foramen width measurements than those who did not develop C5 palsy (2.16+/-1.04 vs 3.31+/-1.25, p=0.023 on the right; 1.84+/-0.80 vs 3.02+/-1.25, p=0.014 on the left). When controlling for technique, CCI, age, BMI, and myelomalacia, multivariate regression analysis revealed increasing levels of laminectomy to be a significant independent predictor of C5 palsy (1.602 (2.258-1.136) for each additional level decompressed, p=0.007). The cut-off value for levels decompressed via laminectomy was determined to be 3.50 levels (>=0.7 AUC <=0.8). Postoperative foramen width was also an independent risk factor for C5 palsy (0.009 (0.000-0.726), p=0.035), it was determined that risk of C5 palsy increases at <2.625mm foramen width (>=0.8 AUC <=0.9).
CONCLUSION(S): C5 palsy following cervical spine surgery is correlated with residual postoperative foraminal stenosis and posterior surgery with increasing number levels decompressed. Patients undergoing more than 3.5 level laminectomy with less than 2.625mm foramen width postoperatively are at highest risk of developing C5 palsy. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs.