Lehman, Ronald A.

Study Design: Single-center retrospective cohort study. Objective: To determine if the 4-rod construct (4RC) is protective against the occurrence of rod fractures when compared with the 3-rod construct (3RC) in adult spinal deformity (ASD) patients with long fusions to the sacrum. Summary of Background Data: Past studies have explored the different outcomes in subjects with dual-rod versus multirod constructs. There is a lack of literature distinguishing the ramifications of 3RC versus 4RC, particularly in the prevalence of rod fractures and rod fractures requiring subsequent revision surgery as a result of pseudarthrosis. Methods: ASD patients undergoing long instrumented fusions to the sacrum were dichotomized between the 3RC and 4RC cohorts. Outcomes of interest include the occurrence of rod fractures (RFs) and RFs requiring revision (RFR). Two-tailed independent-sample t test with Welch's correction and χ 2 /Fisher exact test were used for continuous and categorical variables, respectively. Multivariable logistic regression analysis was performed to assess whether the 4RC is protective against rod fractures when compared with the 3RC. Results: One hundred forty-five patients with a minimum 2-year follow-up were included (3RC=57, 4RC=88). Four RC had a greater body mass index (BMI) ( P =0.002), longer operating room (OR) time ( P =0.002), greater estimated blood loss (EBL) ( P =0.002), total instrumented levels (TIL) ( P =0.028), and more 3-column osteotomies (3COs) performed ( P =0.028). Four RC had greater baseline coronal vertical axis (CVA) (28.2±24.9 vs. 18.5±16.9 mm, P =0.006) and sagittal vertical axis (SVA) (55.1±64.8 vs. 30.4±41.8 mm, P =0.006). Three RC had a greater rate of RF (28.1% vs. 14.8%, P =0.0506) and RFR (14.9% vs. 10.2%, P =0.486) when compared with 4RC, but these findings were not statistically significant. After controlling for BMI, the use of 3-column osteotomies, total instrumented levels, change in coronal alignment (∆CVA), change in sagittal alignment (∆SVA), use of bone morphogenetic protein, and number of interbody fusions, 3RC was associated with 4.93× greater odds of experiencing RFs ( P =0.0078). However, significance fell short when adjusting for the occurrence of RFR [OR=2.58 (0.60–11.19), P =0.2067]. Conclusion: ASD patients having long fusions to the sacrum with 4RC across the lumbosacral junction are shown to be at lesser risk of developing rod fractures but not revision surgery as compared with 3RC at 2-year follow-up.

Study Design: Single-center retrospective analysis. Objective: To establish an empirically derived threshold to define both coronal and sagittal malalignment (CM & SM) based on preoperative patient-reported outcomes (PROs). Summary of Background Data: Currently, no radiographic alignment threshold defines preoperative CM in adult spinal deformity (ASD) patients based on disability. In a cohort of ASD patients undergoing corrective surgery, we sought to establish a threshold to define both CM and SM based on PRO and assess the clinical impact of CM and combined with SM. Methods: ASD patients with ≥6 level fusions were included. CVA and SVA were measured. PROs included preoperative ODI and SRS-22r scores. CVA and SVA thresholds were derived to accurately differentiate patients with ODI >40 and SRS-pain+function <5. Patients were then separated into 4 groups: (1) neutral alignment (NA); (2) CM; (3) SM; and (4) combined coronal and sagittal malalignment (CCSM). Results: Totally, 368 patients were included. Thresholds to distinguish patients with ODI ≥40 and SRS-pain/function <5 were: (1) CVA=3.96 cm (ODI) and 3.17 cm (SRS); (2) SVA=4.97 cm (ODI) and 7.52 cm (SRS). The lower numbers were chosen to define each threshold: CVA=3 cm and SVA=5 cm. Alignment breakdown was: NA=179 (48.6%), CM=66 (17.9%), SM=65 (17.7%), and CCSM=58 (15.8%). Both SM=( P =0.006) and CCSM ( P <0.001) patients had significantly worse ODI scores than NA patients, and CCSM patients were significantly worse than SM alone ( P =0.010). On the basis of preoperative total SRS-22r scores, only CCSM ( P =0.003) patients were significantly worse than the NA group. CVA significantly correlated with 4/7 (57.1%) preoperative PROs (ODI/SRS-total/function/image), while SVA correlated with 5/7 (71.4%) preoperative PROs (ODI/SRS-total/function/image/pain). A linear relationship was seen between increasing CVA and worsening ODI (β=0.92, 95% CI: 0.37–1.48, P =0.001). A significant and slightly stronger relationship was seen between increasing SVA and worsening ODI (β=1.28, 95% CI: 1.00–1.56, P <0.001). Conclusions: CM and SM thresholds that accurately distinguished ASD patients with severe pain and disability preoperatively were 3 cm for CVA and 5 cm for SVA, respectively. Preoperative CM was significantly associated with worse ODI, SRS-22r total/function/image scores. CCSM led to more disability than SM alone.

OBJECTIVE The objective of this study was to compare a multiple pelvic screw fixation strategy (dual bilateral 4 pelvic screw fixation [4PvS]) with the use of single bilateral 2 pelvic screw fixation (2PvS), with the aim of addressing lumbosacral junction stability. METHODS This analysis is a single-center, retrospective review of ASD patients treated between 2015 and 2021. All patients had a minimum 2-year follow-up and spinal fusion to the sacrum without sacroiliac fusion and met at least one radiographic and procedural criterion: pelvic incidence–lumbar lordosis ≥ 20°, T1 pelvic angle ≥ 20°, sagittal vertical axis ≥ 7.5 cm, scoliosis ≥ 50°, three-column osteotomy, or spinal fusion of ≥ 8 levels. Two sacropelvic fixation methods were compared: 4PvS versus 2PvS. Primary outcomes included spinal implant-related reoperation and screw breakage, while secondary outcomes included reoperation for symptomatic pelvic screws, screw loosening or bending, L5–S1 pseudarthrosis, and patient-reported outcomes. Propensity score matching and inverse probability of treatment weighting (IPTW) were used to minimize selection bias and estimate causal treatment effects. Clinical outcomes were assessed using conditional multivariable logistic regression. RESULTS In this study of 406 patients (67.98% female, mean age 64.48 years), 349 patients (85.96%) received 2PvS and 57 (14.04%) received 4PvS. Age (OR 1.081, 95% CI 1.027–1.145) and total number of osteotomies (OR 1.180, 95% CI 1.048–1.355) emerged as independent predictors of receiving the 4PvS technique. In unmatched cohorts (n = 406), 2-year implant-related reoperation rates (p = 0.1896) and pelvic screw breakage rates (p = 0.2498) were not significantly different between groups. However, in the 4:1 propensity score–matched cohort, the 2-year reoperation rate (10.53% for 2PvS vs 3.51% for 4PvS; OR 3.27, 95% CI 1.10–9.74 [p = 0.0312]) and the pelvic screw breakage rate (9.21% for 2PvS vs 3.51% for 4PvS; OR 2.87, 95% CI 1.08–7.63 [p = 0.0349]) were significantly higher among the 2PvS groups. The IPTW analysis confirmed these findings, with reoperation rates of 10.45% for 2PvS and 1.18% for 4PvS (p = 0.0244) and pelvic screw breakage rates of 8.72% and 1.18%, respectively (p = 0.0477). A safety assessment revealed comparable operative times and intra- and perioperative complications between the two techniques. CONCLUSIONS Patients who underwent 4PvS demonstrated significantly lower 2-year implant-related reoperation and pelvic screw breakage rates compared with 2PvS, with no differences in intraoperative or perioperative complications.

Study Design. Delphi method. Objective. To gain consensus on the following questions: (1) When should anticoagulation/antiplatelet (AC/AP) medication be stopped before elective spine surgery?; (2) When should AC/AP medication be restarted after elective spine surgery?; (3) When, how, and in whom should venous thromboembolism (VTE) chemoprophylaxis be started after elective spinal surgery? Summary of Background Data. VTE can lead to significant morbidity after adult spine surgery, yet postoperative VTE prophylaxis practices vary considerably. The management of preoperative AC/AP medication is similarly heterogeneous. Materials and Methods. Delphi method of consensus development consisting of three rounds (January 26, 2021, to June 21, 2021). Results. Twenty-one spine surgeons were invited, and 20 surgeons completed all rounds of questioning. Consensus (>70% agreement) was achieved in 26/27 items. Group consensus stated that preoperative Direct Oral Anticoagulants should be stopped two days before surgery, warfarin stopped five days before surgery, and all remaining AC/AP medication and aspirin should be stopped seven days before surgery. For restarting AC/AP medication postoperatively, consensus was achieved for low-risk/medium-risk/high-risk patients in 5/5 risk factors (VTE history/cardiac/ambulation status/anterior approach/operation). The low/medium/high thresholds were POD7/POD5/POD2, respectively. For VTE chemoprophylaxis, consensus was achieved for low-risk/medium-risk/high-risk patients in 12/13 risk factors (age/BMI/VTE history/cardiac/cancer/hormone therapy/operation/anterior approach/staged separate days/staged same days/operative time/transfusion). The one area that did not gain consensus was same-day staged surgery. The low-threshold/medium-threshold/high-threshold ranges were postoperative day 5 (POD5) or none/POD3-4/POD1-2, respectively. Additional VTE chemoprophylaxis considerations that gained consensus were POD1 defined as the morning after surgery regardless of operating finishing time, enoxaparin as the medication of choice, and standardized, rather than weight-based, dose given once per day. Conclusions. In the first known Delphi study to address anticoagulation/antiplatelet recommendations for elective spine surgery (preoperatively and postoperatively); our Delphi consensus recommendations from 20 spine surgeons achieved consensus on 26/27 items. These results will potentially help standardize the management of preoperative AC/AP medication and VTE chemoprophylaxis after adult elective spine surgery.

Study Design: Prospective single-cohort analysis. Objectives: To compare the outcomes/complications of 2 robotic systems for spine surgery. Methods: Adult patients (≥18-years-old) who underwent robot-assisted spine surgery from 2016-2019 were assessed. A propensity score matching (PSM) algorithm was used to match Mazor X to Renaissance cases. Preoperative CT scan for planning and an intraoperative O-arm for screw evaluation were preformed. Outcomes included screw accuracy, robot time/screw, robot abandonment, and radiation. Screw accuracy was measured using Vitrea Core software by 2 orthopedic surgeons. Screw breach was measured according to the Gertzbein/Robbins classification. Results: After PSA, a total of 65 patients (Renaissance: 22 vs. X: 43) were included. Patient/operative factors were similar between robot systems ( P > .05). The pedicle screw accuracy was similar between robots (Renaissance: 1.1%% vs. X: 1.3%, P = .786); however, the S2AI screw breach rate was significantly lower for the X (Renaissance: 9.5% vs. X: 1.2%, P = .025). Robot time per screw was not statistically different (Renaissance: 4.6 minutes vs. X: 3.9 minutes, P = .246). The X was more reliable with an abandonment rate of 2.3% vs. Renaissance:22.7%, P = .007. Radiation exposure were not different between robot systems. Non-robot related complications including dural tear, loss of motor/sensory function, and blood transfusion were similar between robot systems. Conclusion: This is the first comparative analyses of screw accuracy, robot time/screw, robot abandonment, and radiation exposure between the Mazor X and Renaissance systems. There are substantial improvements in the X robot, particularly in the perioperative planning processes, which likely contribute to the X’s superiority in S2AI screw accuracy by nearly 8-fold and robot reliability by nearly 10-fold.

Purpose: Anterior cervical discectomy and fusion has a low but well-established profile of adverse events. The goal of this study was to gauge surgeon opinion regarding the frequency and acceptability of these events. Methods: A 2-page survey was distributed to attendees at the 2015 Cervical Spine Research Society (CSRS) meeting. Respondents were asked to categorize 18 anterior cervical discectomy and fusion–related adverse events as either: “common and acceptable,” “uncommon and acceptable,” “uncommon and sometimes acceptable,” or “uncommon and unacceptable.” Results were compiled to generate the relative frequency of these responses for each complication. Responses for each complication event were also compared between respondents based on practice location (US vs. non-US), primary specialty (orthopedics vs. neurosurgery) and years in practice. Results: Of 150 surveys distributed, 115 responses were received (76.7% response rate), with the majority of respondents found to be US-based (71.3%) orthopedic surgeons (82.6%). Wrong level surgery, esophageal injury, retained drain, and spinal cord injury were considered by most to be unacceptable and uncommon complications. Dysphagia and adjacent segment disease occurred most often, but were deemed acceptable complications. Although surgeon experience and primary specialty had little impact on responses, practice location was found to significantly influence responses for 12 of 18 complications, with non-US surgeons found to categorize events more toward the uncommon and unacceptable end of the spectrum as compared with US surgeons. Conclusions: These results serve to aid communication and transparency within the field of spine surgery, and will help to inform future quality improvement and best practice initiatives.