CT based bone mineral density as a predictor of proximal junctional fractures.

Background: Proximal junctional fractures (PJFr) can be a catastrophic complication associated with adult spinal deformity surgery. Osteoporosis can be a major risk factor for the cause of PJFr. Recent studies suggest using surrogate computed tomography (CT) scans in place of spinal dual-energy x-ray absorptiometry (DEXA) scores for bone mineral density (BMD). Investigate the feasibility of using preoperative CT based bone mineral density at upper instrumented vertebrae (UIV) and one level proximally (UIV+1) and distally (UIV-1) to predict the possibility of PJFr risk. Methods: Retrospective two-academic center case-controlled study, reviewed consecutive adult spinal deformity surgeries; included constructs encompassing at least five fusion levels and fusions to pelvis. Examined demographic, surgical, and radiographic data preoperatively, postoperatively, and final follow-up. Formed groups based on type of proximal junctional deformity (PJD): Control (no PJD), proximal junctional kyphosis (PJK) and PJFr. Preoperative CT BMD values measured in Hounsfield units (HU) for sagittal and axial planes at UIV, UIV+1, and UIV-1 and compared between groups. Results: N=92 patients. Preoperative CT scan BMD values were significantly lower in PJFr vs. control at: UIV+1 in sagittal (p=0.007), axial (p=0.02) planes; UIV sagittal (p=0.04) and axial (p=0.03) planes; and UIV-1 sagittal (p=0.05) plane. Similarly, lower CT scan BMD values noted in PJFr vs. PJK at: UIV+1 in sagittal (p=0.04) and axial (p=0.03) planes. Trend seen with lower CT scan BMD values at UIV+1 level in PJFr vs. PJK in sagittal (p=0.12) and axial (p=0.10) planes. Preoperative global sagittal imbalance measurements significantly lower in control, but comparable between PJK and PJFr. Conclusions: Higher preoperative global sagittal imbalance with lower preoperative CT BMD values at UIV and UIV+1 vertebral body may increase the risk of proximal junctional fractures after adult spine deformity surgery. Proximal junctional hooks may supplement the pathogenesis. Readers should note the small sample size.Level of Evidence: 3.

Utility of the novel guide catheter in mechanical thrombectomy for emergent large vessel occlusion stroke.

BACKGROUND: A number of large bore guide catheters are currently available for use in neuroendovascular surgery. This study represents a multi-institutional retrospective series of patients undergoing mechanical thrombectomy with the use of a TracStar Large Distal Platform (LDP) guide catheter and assessed its performance in vivo in 107 patients. OBJECTIVE: To review a multi-institutional initial experience with the TracStar LDP guide catheter during mechanical thrombectomy for emergent large vessel occlusion (ELVO). METHODS: A retrospective review was performed at two level one stroke centres to include all patients who underwent mechanical thrombectomy and had the TracStar LDP guide catheter used during the intervention. RESULTS: The TracStar LDP guide catheter was successfully used in 107 mechanical thrombectomies. In anterior circulation ELVO, the guide catheter advanced into the cavernous segment of the internal carotid artery in 62.6% (62/99) of cases. In posterior circulation cases, the guide catheter advanced to the basilar artery in 87.5% (7/8) of cases. A thrombolysis in cerebral infarction 2b or greater reperfusion was obtained in 90.7% (97/107). No complications occurred related to the TracStar LDP guide catheter. Three complications occurred with aspiration catheters including a small dissection that did not require further intervention and fracturing of the AXS Catalyst 6 catheter tip in two cases. No thromboembolic events occurred. CONCLUSIONS: The TracStar LDP large bore guide catheter is safe and effective at navigating the tortuous vascular anatomy often encountered during mechanical thrombectomy for stroke. The flexible distal and stiffer proximal components provide a good combination of navigability and support for use in neuroendovascular interventions.

Perioperative subcutaneous methylnaltrexone does not enhance gastrointestinal recovery after posterior short-segment spinal arthrodesis surgery: a randomized controlled trial.

BACKGROUND CONTEXT: Postoperative ileus is a major barrier to gastrointestinal recovery following surgery. Opioid analgesics likely play an important causative role, particularly in spinal or orthopedic surgeries not involving bowel manipulation. Methylnaltrexone, a peripherally-acting µ-opioid receptor antagonist, is a potential prophylactic treatment. PURPOSE: To assess the influence of perioperative subcutaneous methylnaltrexone administration on gastrointestinal recovery following short-segment lumbar arthrodesis surgeries. DESIGN: This is a randomized, double-blind, controlled trial. PATIENT SAMPLE: Eligible patients undergoing posterior short-segment lumbar arthrodesis surgeries at a single institution between February 2019 and April 2021 were enrolled in this study. OUTCOME MEASURES: The primary outcome measure was time-to-first bowel movement. Secondary outcome measures included time-to-discharge/discharge eligibility. Exploratory outcome measures included daily postoperative opioid consumption and pain scores. METHODS: In this study, eligible patients were enrolled to receive either methylnaltrexone or placebo perioperatively. Time-to-bowel movement, time-to-discharge/discharge eligibility, intra and postoperative analgesic administration, and pain scores were recorded and compared. RESULTS: Eighty two patients in total were enrolled; 41 to the methylnaltrexone and 41 to the placebo group. Both groups were similar in their baseline characteristics. There was no difference in median (range) time-to-bowel movement between the 2 groups [61.8 hours (35.7-93.6) versus 50.7 hours (17.8-110.8), p = .391]. There was also no difference in time-to-discharge/discharge eligibility [105.0 hours (81.0 - 201.3) versus 90.7 (77.5 - 184.5), p=.784]. Finally, there were no differences in either postoperative opioid consumption or numeric rating scores for back, leg, or abdominal pain on postoperative days 0 to 4 (p>.05). CONCLUSIONS: Methylnaltrexone did not accelerate gastrointestinal recovery and did not affect opioid consumption or pain scores following short-segment spinal surgery as compared to placebo. Additional studies will be needed to identify effective opioid receptor antagonist dosing regimens for patients undergoing either short- or long-segment spinal arthrodesis procedures.

Baseline parameters and the prediction of treatment failure in patients with intravenous drug use-associated spinal epidural abscesses.

OBJECTIVE: Despite the increasing incidence of spinal epidural abscess (SEA), the baseline parameters potentially predictive of treatment failure remain poorly characterized. In this study, the authors identify the relevant baseline parameters that predict multimodal treatment failure in patients with either intravenous drug use (IVDU)-associated SEA or non-IVDU-associated SEA. METHODS: The authors reviewed the electronic medical records of a large institutional series of consecutive patients with diagnosed SEA between January 2011 and December 2017 to characterize epidemiological trends as well as the complement of baseline measures that are predictive of failure after multimodal treatment in patients with and without concomitant IVDU. The independent impact of clinical and imaging factors in detecting treatment failure was assessed by performing stepwise binary logistic regression analysis. RESULTS: A total of 324 consecutive patients with diagnosed SEA were identified. Overall, 226 patients (69.8%) had SEA related to other causes and 98 (30.2%) had a history of recent IVDU. While non-IVDU SEA admission rates remained constant, year-over-year admissions of patients with IVDU SEA nearly tripled. At baseline, patients with IVDU SEA were distinct in many respects including younger age, greater unemployment and disability, less frequent diabetes mellitus (DM), and more frequent methicillin-resistant Staphylococcus aureus infection. However, differences in length of stay, loss to follow-up, and treatment failure did not reach statistical significance between the groups. The authors constructed independent multivariate logistic regression models for treatment failure based on identified parameters in the two cohorts. For the non-IVDU cohort, the authors identified four variables as independent factors: DM, hepatitis B/C, osteomyelitis, and compression deformity severity. In contrast, for patients with IVDU, the authors identified three variables: albumin, endocarditis, and endplate destruction. Receiver operating characteristic and area under the curve (AUC) analyses were undertaken for the multivariate models predicting the likelihood of treatment failure in the two cohorts (AUC = 0.88 and 0.89, respectively), demonstrating that the derived models could adequately predict the risk of multimodal treatment failure. Treatment failure risk factor point scales were derived for the identified variables separately for both cohorts. CONCLUSIONS: Patients with IVDU SEA represent a unique population with a distinct set of baseline parameters that predict treatment failure. Identification of relevant prognosticating factors will allow for the design of tailored treatment and follow-up regimens.

Design and feasibility of a double-blind, randomized trial of peri-operative methylnaltrexone for postoperative ileus prevention after adult spinal arthrodesis.

BACKGROUND: Postoperative ileus (POI) is a common complication with no proven prophylactic measures in place. While perioperative opioid use has been implicated in POI development, current treatments fail to target this disease mechanism. Methylnaltrexone (MNTX) has been used to prevent the effects of opioids on the bowel and could reduce the incidence of POI when administered preoperatively. METHODS: In this phase IIb randomized controlled trial, we assessed the effect of perioperative MNTX on time-to-first-bowel movement following spinal arthrodesis surgeries. RESULTS: 82 patients were randomly selected in a 1:1 ratio to be included in either the treatment or placebo groups. Comparison of relevant factors of included patients to patients who refused to participate (n = 21) and to a prior retrospective series (n = 241) revealed no differences in age, male sex, liver disease, and number of surgical levels. Overall treatment fidelity (98% adherence) and retention (100% at one-month follow-up) were high. The predicted POI incidence (9.3-11.1%) was also equivalent to a prior retrospective series. However, the overall observed POI incidence (3.7%) was lower than expected, which could reflect a superimposed 'trial effect' related to standardized care in a research setting. CONCLUSIONS: Since exposure to significant opioid doses represents a barrier to enhanced recovery after surgery, the results of this innovative trial may provide further guidance for the peri-operative use of opioid-receptor blockers. Here, we show that MNTX can be effectively administered in the peri-operative period with appropriate follow-up achieved in a representative population of patients undergoing spinal surgery. TRIAL REGISTRATION NUMBERS: Clinicaltrials.gov - NCT03852524 and Institutional Review Board - 2018H0260.

Development of a postoperative ileus risk assessment scale: identification of intraoperative opioid exposure as a significant predictor after spinal surgery.

OBJECTIVE: Postoperative ileus (POI) is associated with abdominal pain, nausea, vomiting, and delayed mobilization that in turn lead to diminished patient satisfaction, increased hospital length of stay (LOS), and increased healthcare costs. In this study, the authors developed a risk assessment scale to predict the likelihood of developing POI following spinal surgery. METHODS: The authors undertook a retrospective review of a prospectively maintained registry of consecutive patients who underwent arthrodesis/fusion surgeries between May 2013 and December 2017. They extracted clinical information, including cumulative intraoperative and postoperative opioid doses using standardized converted morphine milligram equivalent (MME) values. Univariate and multivariate analyses were performed and several categorical and continuous variables were evaluated in a binary logistic regression model built with backward elimination to assess for independent predictors. A points-based prediction model was developed and validated to determine the risk of POI. RESULTS: A total of 334 patients who underwent spinal fusion surgeries were included. Fifty-six patients (16.8%) developed POI, more frequently in those who underwent long-segment surgeries compared to short-segment surgeries (33.3% vs 10.4%; p < 0.001). POI was associated with an increased LOS when compared with patients who did not develop POI (8.0 ± 4.5 days vs 4.4 ± 2.4 days; p < 0.01). The incidences of liver disease (16% vs 3.7%; p = 0.01) and substance abuse history (12.0% vs 3.2%; p = 0.04) were higher in POI patients than non-POI patients undergoing short-segment surgeries. While the incidences of preoperative opioid intake (p = 0.23) and cumulative 24-hour (87.7 MME vs 73.2 MME; p = 0.08) and 72-hour (225.6 MME vs 221.4 MME; p = 0.87) postoperative opioid administration were not different, remifentanil (3059.3 µg vs 1821.5 µg; p < 0.01) and overall intraoperative opioid (326.7 MME vs 201.7 MME; p < 0.01) dosing were increased in the POI group. The authors derived a multivariate model based on the 5 most significant factors predictive of POI (number of surgical levels, intraoperative MME, liver disease, age, and history of substance abuse) and calculated relative POI risks using a derived 32-point system. CONCLUSIONS: Intraoperative opioid administration, incorporated in a comprehensive risk assessment scale, represents an early and potentially modifiable predictor of POI. These data indicate that potential preventive strategies, implemented as part of enhanced recovery after surgery protocols, could be instituted in the preoperative phase of care to reduce POI incidence.

Sublaminar banding as an adjunct to pedicle screw-rod constructs: a review and technical note on novel hybrid constructs in spinal deformity surgery.

Sublaminar implants that encircle cortical bone are well-established adjuncts to pedicle screw-rod constructs in pediatric deformity surgery. Sublaminar bands (SLBs) in particular carry the advantage of relatively greater bone contact surface area as compared to wires and pullout loads that are independent of bone mineral density, in contrast to pedicle screws. Whereas the relevant technical considerations have been reported for pediatric deformity correction, an understanding of the relative procedural specifics of these techniques is missing for adult spinal deformity (ASD), despite several case series that have used distinct posterior tethering techniques for proximal junctional kyphosis prevention. In this paper, the authors summarize the relevant literature and describe a novel technique wherein bilateral tensioned SLBs are introduced at the nonfused proximal junctional level of long-segment ASD constructs.

Biomechanical assessment of proximal junctional semi-rigid fixation in long-segment thoracolumbar constructs.

OBJECTIVEProximal junctional kyphosis (PJK) and failure (PJF) are potentially catastrophic complications that result from abrupt changes in stress across rigid instrumented and mobile non-fused segments of the spine (transition zone) after adult spinal deformity surgery. Recently, data have indicated that extension (widening) of the transitional zone via use of proximal junctional (PJ) semi-rigid fixation can mitigate this complication. To assess the biomechanical effectiveness of 3 semi-rigid fixation constructs (compared to pedicle screw fixation alone), the authors performed cadaveric studies that measured the extent of PJ motion and intradiscal pressure changes (ΔIDP).METHODSTo measure flexibility and ΔIDP at the PJ segments, moments in flexion, extension, lateral bending (LB), and torsion were conducted in 13 fresh-frozen human cadaveric specimens. Five testing cycles were conducted, including intact (INT), T10-L2 pedicle screw-rod fixation alone (PSF), supplemental hybrid T9 Mersilene tape insertion (MT), hybrid T9 sublaminar band insertion (SLB1), and hybrid T8/T9 sublaminar band insertion (SLB2).RESULTSCompared to PSF, SLB1 significantly reduced flexibility at the level rostral to the upper-instrumented vertebral level (UIV+1) under moments in 3 directions (flexion, LB, and torsion, p ≤ 0.01). SLB2 significantly reduced motion in all directions at UIV+1 (flexion, extension, LB, torsion, p < 0.05) and at UIV+2 (LB, torsion, p ≤ 0.03). MT only reduced flexibility in extension at UIV+1 (p = 0.02). All 3 constructs revealed significant reductions in ΔIDP at UIV+1 in flexion (MT, SLB1, SLB2, p ≤ 0.02) and torsion (MT, SLB1, SLB2, p ≤ 0.05), while SLB1 and SLB2 significantly reduced ΔIDP in extension (SLB1, SLB2, p ≤ 0.02) and SLB2 reduced ΔIDP in LB (p = 0.05). At UIV+2, SLB2 similarly significantly reduced ΔIDP in extension, LB, and torsion (p ≤ 0.05).CONCLUSIONSCompared to MT, the SLB1 and SLB2 constructs significantly reduced flexibility and ΔIDP in various directions through the application of robust anteroposterior force vectors at UIV+1 and UIV+2. These findings indicate that semi-rigid sublaminar banding can most effectively expand the transition zone and mitigate stresses at the PJ levels of long-segment thoracolumbar constructs.

Comparative Utility of Dynamic and Static Imaging in the Management of Lumbar Spondylolisthesis.

OBJECTIVE: Segmental instability traditionally is investigated with flexion and extension (F/E) radiographs. We sought to determine whether motion between upright and supine (U/S) views can serve as an alternative sensitive diagnostic tool that predicts similar outcomes. METHODS: Ambispective collection of data was performed for 222 consecutive patients who underwent transforaminal lumbar interbody fusion. Patients were divided into either group 1 (≥3 mm spondylolisthesis difference between F/E radiographs) or group 2 (≥3 mm spondylolisthesis difference between U/S imaging and otherwise not meeting group 1 criteria). RESULTS: In total, 77 patients met all inclusion/exclusion criteria. Patients in group 1 (n = 26) and group 2 (n = 51) did not differ with respect to key demographic criteria. Average clinical follow-up for groups 1 and 2 were 31.8 and 35.6 months (P = 0.43). Average spondylolisthesis was 8.1 mm and 8.0 mm for groups 1 and 2 (P = 0.93). The incidence of facet joint hyperintensity on T2-weighted magnetic resonance imaging and average maximal facet joint widening (P > 0.2) did not differ between groups. Average F/E slip change was 5.0 mm for group 1 and average U/S slip change was 5.2 mm for group 2. For both groups, Numeric Rating Scale Back Pain and Numeric Rating Scale Leg Pain, Oswestry Disability Index v2.1a, and Short-Form 36 RAND (P < 0.02) improved significantly after surgery. Furthermore, ΔNumeric Rating Scale Back Pain, ΔNumeric Rating Scale Leg Pain, ΔOswestry Disability Index v2.1a, and ΔShort-Form 36 RAND (P > 0.2) were not significantly different between groups. CONCLUSIONS: No differences in outcomes were noted between patients based on either imaging criteria. These data suggest that static U/S imaging may identify a distinct group of patients who may benefit from transforaminal lumbar interbody fusion surgery.

Surgical management of adult type 1 split cord malformation. Report of two cases with literature review.

Split cord malformation (SCM) is a rare form of spinal dysraphism wherein the spinal cord is divided longitudinally into two distinct hemicords. Surgery is usually performed in children while management in adults, who rarely manifest symptoms, remains controversial. Both expectant management and prophylactic surgery have been variously advocated. The present article describes our experience in two adult patients with predominant pain-related complaints who underwent surgical excision of type 1 SCM lesions. A comprehensive review of the literature on SCM in adults is also provided. While pain, disability, and quality of life scores improved in these two patients, further larger studies will be required to define the role of surgery in adults with type 1 SCM and a pain-dominant presentation.

Prospective assessment of the safety and early outcomes of sublaminar band placement for the prevention of proximal junctional kyphosis.

OBJECTIVE Proximal junctional kyphosis (PJK) can progress to proximal junctional failure (PJF), a widely recognized early and serious complication of multisegment spinal instrumentation for the treatment of adult spinal deformity (ASD). Sublaminar band placement has been suggested as a possible technique to prevent PJK and PJF but carries the theoretical possibility of a paradoxical increase in these complications as a result of the required muscle dissection and posterior ligamentous disruption. In this study, the authors prospectively assess the safety as well as the early clinical and radiological outcomes of sublaminar band insertion at the upper instrumented vertebra (UIV) plus 1 level (UIV+1). METHODS Between August 2015 and February 2017, 40 consecutive patients underwent either upper (T2-4) or lower (T8-10) thoracic sublaminar band placement at the UIV+1 during long-segment thoracolumbar arthrodesis surgery. Outcome measures were prospectively collected and uploaded to a web-based REDCap database specifically designed to include demographic, clinical, and radiological data. All patients underwent clinical assessment, as well as radiological assessment with anteroposterior and lateral 36-inch whole-spine standing radiographs both pre- and postoperatively. RESULTS Forty patients (24 women and 16 men) were included in this study. Median age at surgery was 64.0 years with an IQR of 57.7-70.0 years. Median follow-up was 12 months (IQR 6-15 months). Three procedure-related complications were noted, including 2 intraoperative cerebrospinal spinal fluid leaks and 1 transient neurological deficit. Median visual analog scale (VAS) scores for back pain significantly improved after surgery (preoperatively: 8.0, IQR 6.0-10.0; 1-year follow-up: 2.0, IQR 0.0-6.0; p = 0.001). Median Oswestry Disability Index (version 2.1a) scores also significantly improved after surgery (preoperatively: 56.0, IQR 45.0-64.0; 1-year follow-up: 46.0, IQR 22.2-54.0; p < 0.001). Sagittal vertical axis (preoperatively: 9.0 cm, IQR 5.3-11.6 cm; final follow-up: 4.7 cm, IQR 2.0-6.6 cm; p < 0.001), pelvic incidence-lumbar lordosis mismatch (24.7°, IQR 11.2°-31.2°; 7.7°, IQR -1.2° to 19.5°; p < 0.001), and pelvic tilt (28.7°, IQR 20.4°-32.6°; 17.1°, IQR 10.8°-25.2°; p < 0.001) were all improved at the final follow-up. While proximal junctional (PJ) Cobb angles increased overall at the final follow-up (preoperatively: 4.2°, IQR 1.9°-7.4°; final follow-up: 8.0°, IQR 5.8°-10.3°; p = 0.002), the significant increase was primarily noted starting at the immediate postoperative time point (7.2°, IQR 4.4°-11.8°; p = 0.001) and not beyond. Three patients (7.5%) developed radiological PJK (mean ΔPJ Cobb 15.5°), while there were no instances of PJF in this cohort. CONCLUSIONS Sublaminar band placement at the UIV+1 during long-segment thoracolumbar instrumented arthrodesis is relatively safe and is not associated with an increased rate of PJK. Moreover, no subjects developed PJF. Prospective large-scale and long-term analysis is needed to define the potential benefit of sublaminar bands in reducing the incidence of PJK and PJF following surgery for ASD. Clinical trial registration no.: NCT02411799 (clinicaltrials.gov).