Frequency and predictors of complication clustering within 30 days of spinal fusion surgery: a study of children with neuromuscular scoliosis

PURPOSE

There is limited information on the clustering or co-occurrence of complications after spinal fusion surgery for neuromuscular disease in children. We aimed to identify the frequency and predictive factors of co-occurring perioperative complications in these children.

METHODS

In this retrospective database cohort study, we identified children (ages 10-18 years) with neuromuscular scoliosis who underwent elective spinal fusion in 2012-2020 from the National Surgical Quality Improvement Program-Pediatric database. The rates of co-occurring complications within 30 days were calculated, and associated factors were identified by logistic regression analysis. Correlation between a number of complications and outcomes was assessed.

RESULTS

Approximately 11% (709/6677 children with neuromuscular scoliosis undergoing spinal fusion had co-occurring complications: 7% experienced two complications and 4% experienced ≥ 3. The most common complication was bleeding/transfusion (80%), which most frequently co-occurred with pneumonia (24%) and reintubation (18%). Surgical time ≥ 400 min (odds ratio (OR) 1.49 [95% confidence interval (CI) 1.25-1.75]), fusion ≥ 13 levels (1.42 [1.13-1.79]), and pelvic fixation (OR 1.21 [1.01, 1.44]) were identified as procedural factors that independently predicted concurrent complications. Clinical risk factors for co-occurring complications included an American Society of Anesthesiologist physical status classification ≥ 3 (1.73 [1.27-2.37]), structural pulmonary/airway abnormalities (1.24 [1.01-1.52]), impaired cognitive status (1.80 [1.41-2.30]), seizure disorder (1.36 [1.12-1.67]), hematologic disorder (1.40 [1.03-1.91], preoperative nutritional support (1.34 [1.08-1.72]), and congenital malformations (1.20 [1.01-1.44]). Preoperative tracheostomy was protective against concurrent complications (0.62 [0.43-0.89]). Significant correlations were found between number of complications and length of stay, non-home discharge, readmissions, and death.

CONCLUSION

Longer surgical time (≥ 400 min), fusion ≥ 13 levels and pelvic fixation are surgical risk factors independently associated with co-occurring complications, which were associated with poorer patient outcomes. Recognizing identified nonmodifiable risk factors might also be important for preoperative planning and risk stratification of children with neuromuscular scoliosis requiring spinal fusion.

LEVEL OF EVIDENCE

Level IV evidence.

Epidemiology of Gunshot-Related Spinal Injuries and Related Risk Factors for In-Hospital Mortality in the United States from 2015-2019: A National Trauma Data Bank Analysis

Firearm injuries in the U.S. pose a significant public health burden, but data on gunshot wounds (GSWs) specifically involving the spine are scarce. We examined epidemiological trends in GSWs to the spine and associated spinal cord injury (SCI) and mortality rates. This was a cross-sectional study of data from level I-III trauma centers in the U.S. participating in the American College of Surgeons National Trauma Data Bank (ACS NTDB) in 2015-2019. We identified adult and pediatric patients presenting with GSW and evaluated those with Abbreviated Injury Scale codes indicating spinal involvement and SCI. We assessed in-hospital mortality and GSW-related SCI. A total of 5,021,316 patients were enrolled in the ACS NTDB. Of the 107,233 patients (2.1% of total) presenting with GSW, 9023 (8.4%) patients had spine involvement. Overall rates of GSW and spinal GSW were similar across years. The most common cause of spinal GSW injury was assault (86.7%). The cervical spine was involved in 24.2% of patients, thoracic spine in 42.8%, and lumbar spine in 39.7%. Cervical SCI was present in 8.7% of all spinal GSW (35.7% of cervical GSW), thoracic SCI in 17.4% (40.6% of thoracic GSW), and lumbar SCI in 8.1% (20.3% of lumbar GSW). The mean patient age was 29.0 ± 12.2 years, 88.5% were male, 62.4% were black, 23.7% were white, and 13.9% were another race. Blood alcohol content was ≥0.08 in 12.1%, and illicit drugs were positive in 24.4%. In-hospital mortality was high in patients with spinal GSWs (8.1%), and mortality was significantly higher with cervical involvement (18.1%), cervical SCI (30.7%), or thoracic incomplete SCI (13.6%) on univariate analysis. On multi-variate analysis of age (excluding patients <16 years of age), sex, Injury Severity Score (ISS), complete SCI, and spinal area of involvement, only greater patient age (age 40-65 years: adjusted odds ratio [aOR] 1.52, 95% confidence interval [CI] 1.09-2.11, p = 0.014; age >65 years: aOR 3.90, 95% CI 2.10-7.27, p < 0.001) and higher ISS (ISS 9-15: aOR 6.65, 95% CI 2.38-18.54, p < 0.001; ISS 16-24: aOR 18.13, 95% CI 6.65-49.44, p < 0.001; ISS >24: aOR 68.44, 95% CI 25.39-184.46, p < 0.001) were independently associated with in-hospital mortality risk after spinal GSW. These results demonstrate that spinal GSW is not uncommon and that older patients with more severe systemic injuries have higher in-hospital mortality risk.

Mid-term and Long-term Outcomes After Total Cervical Disk Arthroplasty Compared With Anterior Cervical Discectomy and Fusion: A Systematic Review and Meta-analysis of Randomized Controlled Trials

STUDY DESIGN

A meta-analysis of randomized controlled trials (RCTs).

OBJECTIVE

The aim of this study was to compare mid-term to long-term outcomes of cervical disk arthroplasty (CDA) with those of anterior cervical discectomy and fusion (ACDF) for the treatment of symptomatic cervical degenerative disk disease.

SUMMARY OF BACKGROUND DATA

After ACDF to treat symptomatic cervical degenerative disk disease, the loss of motion at the index level due to fusion may accelerate adjacent-level disk degeneration. CDA was developed to preserve motion and reduce the risk of adjacent segment degeneration. Early-term to mid-term clinical outcomes from RCTs suggest noninferiority of CDA compared with ACDF, but it remains unclear whether CDA yields better mid-term to long-term outcomes than ACDF.

MATERIALS AND METHODS

Two independent reviewers searched PubMed, Embase, and the Cochrane Library for RCTs with at least 60 months of follow-up. The risk ratio or standardized mean difference (and 95% CIs) were calculated for dichotomous or continuous variables, respectively.

RESULTS

Eighteen reports of 14 RCTs published in 2014-2023 were included. The pooled analysis demonstrated that the CDA group had a significantly greater improvement in neurological success and Neck Disability Index than the ACDF group. The ACDF group exhibited a significantly better improvement in the Short Form-36 Health Survey Physical Component Summary than the CDA group. Radiographic adjacent segment degeneration was significantly lower in the CDA group at 60- and 84-month follow-ups; at 120-month follow-up, there was no significant difference between the 2 groups. Although the overall rate of secondary surgical procedures was significantly lower in the CDA group, we did not observe any significant difference at 60-month follow-up between the CDA and ACDF group and appreciated statistically significant lower rates of radiographic adjacent segment degeneration, and symptomatic adjacent-level disease requiring surgery at 84-month and 108- to 120-month follow-up. The rate of adverse events and the neck and arm pain scores in the CDA group were not significantly different from those of the ACDF group.

CONCLUSIONS

In this meta-analysis of 14 RCTs with 5- to 10-year follow-up data, CDA resulted in significantly better neurological success and Neck Disability Index scores and lower rates of radiographic adjacent segment degeneration, secondary surgical procedures, and symptomatic adjacent-level disease requiring surgery than ACDF. ACDF resulted in improved Short Form-36 Health Survey Physical Component Summary scores. However, the CDA and ACDF groups did not exhibit significant differences in overall changes in neck and arm pain scores or rates of adverse events.

Closed cervical traction techniques: moving into the 21st century

Closed cervical traction for reducing dislocating cervical injuries, deformity correction, or discectomy distraction has been implemented in its modern form since the 1930s. Cervical traction state of the art has not changed significantly since the 1960s, with most reductions performed by using Gardner-Wells tongs or halo traction; however, there are many limitations of traditional weight-pulley traction, including limited reduction efficacy and patient safety shortcomings. In this paper, the authors review the history of cervical traction in the 20th century and the limitations of current traction techniques and describe a novel traction device developed at the University of Utah with robotic actuator load or position control and real-time force-sensing capabilities. Preliminary biomechanical testing results using the novel device in an extension spring loading model, with intact cadavers, and in iatrogenic facet injury cadaveric models demonstrated preliminary safety and efficacy of the device. The authors believe this and future research efforts aimed toward improving the efficacy and safety of cervical traction will help advance the field into the 21st century.

A radiological analysis of pelvic fixation trajectories: patient series

BACKGROUND

Three well-defined methods for pelvic fixation are used for biomechanical support in spine fusion constructs: iliac, recessed iliac, and S2-alar-iliac (S2AI) screws. The authors compared the maximum screw sizes that could be placed with these techniques by using image-guidance software and high-resolution computed tomography scans from 20 randomly selected patients. Six trajectories were plotted per side, beginning at recognized starting points (standard or recessed posterior superior iliac spine [PSIS] or S2AI screw) and ending at the anterior inferior iliac spine (AIIS) or supra-acetabular notch (SAN).

OBSERVATIONS

The mean maximum screw length and width ranged from 80.0 ± 32.2 mm to 140.8 ± 22.6 mm and from 8.25 ± 1.2 mm to 13.0 ± 2.7 mm, respectively, depending on the trajectory. Statistically significant differences in length were found between the standard and recessed PSIS trajectories to the AIIS (p < 0.001) and between the standard PSIS-to-AIIS trajectory and the S2AI-to-AIIS (p = 0.007) or S2AI-to-SAN (p < 0.001) trajectories. The most successful trajectory was the PSIS to SAN (95%, 38/40).

LESSONS

The traditional iliac screw trajectory enabled the longest and widest screw trajectories and highest rate of successful screw placement with the fewest theoretical breaches more reliably than recessed and S2AI trajectories. These findings may help surgeons plan for maximum screw purchase for pelvic fixation.

Efficacy of Intraoperative Neuromonitoring during the Treatment of Cervical Myelopathy

Objective The accuracy of intraoperative neuromonitoring (IONM) during surgery for cervical spondylotic myelopathy (CSM) to detect iatrogenic nervous system injuries while they are reversible remains unknown. We evaluated a cohort of patients who had IONM during surgery to assess accuracy.

Methods Patients who underwent surgical treatment of CSM that included IONM from January 2018 through August 2018 were retrospectively identified. A standardized protocol was used for operative management. Clinical changes and postoperative neurological deficits were evaluated.

Results Among 131 patients in whom IONM was used during their procedure, 42 patients (age 58.2 ± 16.3 years, 54.8% males) showed IONM changes and 89 patients had no change. The reasons for IONM changes varied, and some patients had changes detected via multiple modalities: electromyography (n = 25, 59.5%), somatosensory-evoked potentials (n = 14, 33.3%), motor evoked potentials (n = 13, 31.0%). Three patients, all having baseline deficits before surgery, had postoperative deficits. Among the 89 patients without an IONM change, 4 showed worsened postoperative deficits, which were also seen at last follow-up. The sensitivity of IONM for predicting postoperative neurological change was 42.86% and the specificity was 68.55%. However, most patients (124, 94.7%) in whom IONM was used showed no worsened neurological deficit.

Conclusions IONM shows potential in ensuring stable postoperative neurological outcomes in most patients; however, its clinical use and supportive guidelines remain controversial. In our series, prediction of neurological deficits was poor in contrast to some previous studies. Further refinement of clinical and electrophysiological variables is needed to uniformly predict postoperative neurological outcomes.

Postoperative ileus risk after posterior thoracolumbar fusion performed with total intravenous anesthesia versus inhaled anesthesia

OBJECTIVE

There has been an increase in the use of total intravenous anesthesia (TIVA) for intraoperative neuromonitoring during thoracolumbar posterior spinal fusion (PSF). Although prior studies have identified risk factors for postoperative ileus (PI) after PSF, to the authors' knowledge, PI rates in patients receiving inhaled anesthetic versus TIVA have not been evaluated. In this study the authors analyzed whether TIVA is associated with greater risk of PI in PSF patients.

METHODS

In this retrospective single-institution cohort study, all patients undergoing PSF at the authors' tertiary academic institution from May 2014 to December 2020 were included. Patients undergoing anterior/lateral approaches or who had concurrent abdominal procedures unrelated to ileus in the same admission were excluded. PI was defined using radiographic and/or clinical diagnoses (postoperative radiographs, abdominal CT, and/or ICD-9 or -10 codes) and was confirmed via chart review. The use of TIVA or inhaled anesthetic was captured from the anesthesia record; patients were excluded if they were missing anesthesia technique data. Postoperative occurrence of PI was compared between patients who had TIVA or inhaled anesthetics while controlling for collected demographic, clinical, and surgical variables.

RESULTS

Of the 2819 patients meeting inclusion criteria, 283 (10.0%) had PI (mean ± SD age 59.3 ± 15.8 years; 155 [54.8%] male). The mean patient length of stay was 7.7 ± 5.0 days, which was significantly longer than that of patients without PI (4.9 ± 3.9 days, p < 0.001). Patients with PI had more levels fused (46% of PI patients with ≥ 5 levels fused vs 25% of non-PI patients, p < 0.001) and longer operations (6.0 ± 2.2 vs 5.4 ± 1.9 hours, p < 0.001). TIVA patients were more likely than inhalation-only patients to experience PI, but this finding did not reach significance on univariate analysis (11.0% PI rate vs 8.9%, p = 0.06). After propensity matching 125 non-PI patients and 50 PI patients by age, sex, operative time, and number of levels fused, there was a significant difference in intraoperative opiate dosing between TIVA and inhalational patients (275.7 ± 187.5 intravenous morphine milligram equivalents vs 120.9 ± 155.5, p < 0.001). On multivariate analysis of PI outcome, TIVA was an independently significant predictor (OR 1.45, p = 0.02), as was anesthesia time (OR per hour increase: 1.09, p = 0.03) and ≥ 8 levels fused (OR 1.86, p = 0.01).

CONCLUSIONS

In a large cohort of PSF patients, TIVA was associated with a higher rate of PI compared with inhaled anesthetic. This effect is likely due to higher intraoperative opiate use in these patients.

O-Arm Accuracy and Radiation Exposure in Adult Deformity Surgery

OBJECTIVE

In long thoracolumbar deformity surgery, accurate screw positioning is critical for spinal stability. We assessed pedicle and pelvic screw accuracy and radiation exposure in patients undergoing long thoracolumbar deformity fusion surgery (≥4 levels) involving 3-dimensional fluoroscopy (O-Arm/Stealth) navigation.

METHODS

In this retrospective single-center cohort study, all patients aged >18 years who underwent fusion in 2016-2018 were reviewed. O-Arm images were assessed for screw accuracy. Effective radiation doses were calculated. The primary outcome was pedicle screw accuracy (Heary grade). Secondary outcomes were pelvic fixation screw accuracy, radiation exposure, and screw-related perioperative and postoperative complications or revision surgery within 3 years.

RESULTS

Of 1477 pedicle screws placed in 91 patients (mean 16.41 ± 5.6 screws/patient), 1208 pedicle screws (81.8%) could be evaluated by 3-dimensional imaging after placement. Heary Grade I placement was achieved in 1150 screws (95.2%), Grade II in 47 (3.9%), Grade III in 10 (0.82%), Grade IV in 1 (0.08%), and Grade V in 0; Grade III-V were replaced intraoperatively. One of 60 (1.6%) sacroiliac screws placed showed medial cortical breach and was replaced. The average O-Arm-related effective dose was 29.54 ± 14.29 mSv and effective dose/spin was 8.25 ± 2.65 mSv. No postoperative neurological worsening, vascular injuries, or revision surgeries for screw misplacement were recorded.

CONCLUSIONS

With effective radiation doses similar to those in interventional neuroendovascular procedures, the use of O-Arm in multilevel complex deformity surgery resulted in high screw accuracy, no need for surgical revision because of screw malposition, less additional imaging, and no radiation exposure for the surgical team.

High Failure Rates in Prisoners Undergoing Spine Fusion Surgery

OBJECTIVE

The medical literature on prisoner health care is limited, despite data showing that prisoners experience high rates of physical and mental health challenges. We compared clinical outcomes for prisoners undergoing spine fusion with comparable nonincarcerated patients and determined what factors were implicated in differences in outcomes.

METHODS

Prisoners who underwent spinal fusion in 2011-2021 were retrospectively compared with an age-, sex-, and procedure-matched 3:1 control group of nonincarcerated spinal fusion patients. Fusion failure was confirmed by lack of bridging bone between vertebrae on CT or radiographic images >1 year postoperatively or evidence of instrumentation failure with resultant >2 mm of translation on flexion/extension radiographs.

RESULTS

Twenty-seven identified prisoners were compared with 81 nonincarcerated controls. Ten prisoners and 6 controls experienced nonunion (37% vs. 7%, P < 0.01). Rates of risk factors for nonunion, such as smoking history, elevated body mass index, chronic steroid use, diabetes mellitus, previous spine surgery, and levels fused, were not significantly different between prisoners and controls. Among prisoners, those with nonunion were younger (45 vs. 53 years, P = 0.03), had greater body mass index (34 vs. 29, P = 0.02), and were more likely to undergo reoperation (30% vs. 0%, P = 0.02). Multivariate analysis revealed that prisoners carry a 9.62 increased odds of nonunion compared with controls.

CONCLUSIONS

This is one of few studies investigating health care outcomes in prisoners. We found they had a significantly higher rate of nonunion than matched control patients from the general population treated at the same hospital, suggesting additional measures may be necessary postoperatively to support fusion in prisoners.

Using Frailty Measures to Predict Functional Outcomes and Mortality After Type II Odontoid Fracture in Elderly Patients: A Retrospective Cohort Study

STUDY DESIGN

Single-center retrospective cohort study.

OBJECTIVES

Type II odontoid fractures occur disproportionately among elderly populations and cause significant morbidity and mortality. It is a matter of debate whether these injuries are best managed surgically or conservatively. Our goal was to identify how treatment modalities and patient characteristics correlated with functional outcome and mortality.

METHODS

We identified adult patients (>60 years) with traumatic type II odontoid fractures. We used multivariate regression controlling for patient demographics, Glasgow Coma Scale (GCS) score, Charlson Comorbidity Index (CCI), modified Rankin Scale (mRS) score, modified Frailty Index (mFI-5 and mFI-11), fracture displacement, and conservative vs operative treatment.

RESULTS

Of the 59 patients (mean age 77.9 years), 24 underwent surgical intervention and 35 underwent conservative management. Operatively managed patients were younger (73.4 vs 80.6 years, P < .001) and had higher degree of fracture displacement (3.5 vs 1.0 mm, P = .002) than conservatively managed patients but no other differences in baseline characteristics. Twenty-four patients (40.7%) died within the study period (median time to death: 376 days). There were no differences between treatment groups in functional outcomes (mRS or Frankel Grade) or mortality (33.3% in operative group vs 45.7%, P = .34). There was a statistically significant correlation between higher presentation mRS score and subsequent mortality on multivariate analysis (OR = 2.06, 95% CI 1.04-4.10, P = .039), whereas surgical intervention, age, GCS score, CCI, mFI-5, mFI-11, sex, and fracture displacement were not significantly correlated.

CONCLUSIONS

Mortality after type II odontoid fractures in elderly patients is common. mRS score at presentation may help predict mortality more accurately than other patient factors.

Identification of an Operative Time Threshold for Substantially Increased Postoperative Complications Among Elderly Spine Surgery Patients

STUDY DESIGN

Retrospective cohort study.

OBJECTIVES

To identify whether thresholds exist beyond which operative duration or age increases risks for complications among patients ≥65 years undergoing elective spine surgery.

METHODS

Elective inpatient spine procedures unrelated to infection/trauma/tumor diagnoses in patients <65 years recorded in the 2006-2019 American College of Surgeons National Surgical Quality Improvement database were identified. Univariate analyses was used to compare 30 day complication rates among 5 operative duration and age-stratified groups. To quantify the risk of prolonged operative duration on complications, multivariate analyses were performed controlling for confounders. A generalized linear model was used to assess the individual and combined effect strength of age and operative duration on complication rates.

RESULTS

Among 87,705 patients stratified by operative duration, 30 day complication rates rose nonlinearly as operative duration increased, with a sharp rise after 4.0-4.9 hours (28.3% at 4.0-4.9 hours, 51.7% at ≥5 hours, P < .001). Multivariate analysis found operative duration was independently associated with increased risk of overall complications (odds ratio 1.10→1.69, P < .001) and medical complications (odds ratio 1.19→1.98, P < .001). Although complication rates rose by age (all P < .001), age was not independently predictive of overall complications within any operative duration group on multivariate analysis. Operative duration had a greater effect (η2P = .067) than age (η2P = .003) on overall complication rates.

CONCLUSIONS

Increased operative duration was strongly associated with 30 day complication rates, particularly beyond a threshold of 5 hours. Furthermore, operative duration had a notably larger effect on overall complication rates than age.

Case Series and Systematic Review of Electronic Scooter Crashes and Severe Traumatic Brain Injury

OBJECTIVE

Electric scooters (e-scooters) are an increasingly popular form of transportation, but their use has also resulted in increased incidence of traumatic brain injury (TBI). Previous reports have predominantly described mild TBI with limited attention to other injury patterns. Our objective was to evaluate the impact of e-scooter use on rates of severe TBI.

METHODS

We performed a multicenter retrospective case review of patients who presented with severe TBI (Glasgow Coma Scale score 3-8) related to e-scooter use and undertook a systematic literature review to identify other reports of severe TBI related to e-scooter use.

RESULTS

Of the 19 patients (mean age, 38 ± 16 years; 73.7% male) included in the case series, 13 (68.4%) experienced a fall and 6 (31.6%) were involved in a collision. Various cerebral injury patterns, associated craniofacial fractures, and cervical spine injuries were also seen. Twelve patients (63.2%) underwent intracranial pressure monitor placement and 6 (31.6%) underwent a decompressive hemicraniectomy. Most patients (n = 12; 63.2%) were discharged to acute rehabilitation, with a median modified Rankin Scale score of 2 at 4.9 ± 7.7 months follow-up (52.6% had a good outcome of modified Rankin Scale score ≤2), but 4 patients died of primary injuries. The systematic review identified 18 studies with 77,069 patients between 2019 and 2021, with 37 patients who required intensive care and 6 patients who had neurosurgical intervention.

CONCLUSIONS

Severe TBI after e-scooter use is associated with high morbidity and is likely underdiagnosed in the literature. Awareness and public policies may be helpful to reduce the impact of injury.

L4 Corpectomy: Surgical Approaches and Mitigating the Risk of Femoral Nerve Injuries

OBJECTIVE

Because of the challenging anatomic location, corpectomies are performed less often at the fourth lumbar vertebral body than at other levels. Our objective was to review the literature of L4 corpectomy and anterior column reconstruction.

METHODS

A literature search in the Medline/PubMed database was conducted following the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines to identify all relevant cases and cases series describing corpectomies of the L4 vertebral body using "lumbar" AND "corpectomy" as search terms. We present an illustrative case to describe the technique.

RESULTS

We identified 18 articles with 30 patients who met the search criteria. Including our case illustration, the most common approach used was the lateral retroperitoneal approach (n = 17, 54.8%), of which 8 (26.7%) were performed via a transpsoas approach. Seven (23%) patients underwent corpectomy through a posterior approach, 4 (12.9%) through an anterior retroperitoneal approach, and 3 (10%) through combined anterior and lateral retroperitoneal. The overall complications rate was 19.3% including 1 case each of femoral nerve injury and iatrogenic lumbar nerve root injury.

CONCLUSIONS

Corpectomies of the L4 vertebral body are challenging. None of the various approaches described clearly demonstrates any superiority in mitigating the risk of neural complications. Decision making about which surgical approach to use should be based on patient-specific characteristics.

Neurosurgery at Pearl Harbor: Ralph Cloward’s legacy

Ralph B. Cloward (1908–2000) was the sole neurosurgeon present during the Japanese attack on Pearl Harbor on December 7, 1941. Cloward operated on 42 patients in a span of 4 days during the attacks and was awarded a commendation signed by President Franklin D. Roosevelt in 1945 for his wartime efforts. During the attacks, he primarily treated depressed skull fractures and penetrating shrapnel wounds, but he also treated peripheral nerve and spine injuries in the aftermath. His techniques included innovative advancements such as tantalum cranioplasty plates, electromagnets for intracranial metallic fragment removal, and the application of sulfonamide antibiotic powder within cranial wounds, which had been introduced by military medics for gangrene prevention in 1939 and described for penetrating cranial wounds in 1940. Despite the severity of injuries encountered, only 2 soldiers died in the course of Cloward’s interventions. As the sole neurosurgeon in the Pacific Theater until 1944, he remained in Honolulu through World War II’s duration and gained immense operative experience through his wartime service. Here, the authors review the history of Cloward’s remarkable efforts, techniques, injury patterns treated, and legacy.

Laminectomy at T4 and T5 for Resection of Symptomatic Cavernous Malformation

Although rare, intramedullary spinal cavernous malformations have a 1.4%-6.8% annual hemorrhage risk and can cause significant morbidity.¹ Prior hemorrhage and size >1 cm are risk factors for future hemorrhage that, in addition to notable or progressive symptoms, may justify early surgical intervention.^1,2 In this video, we present key steps in surgical management of a large, symptomatic thoracic cavernous malformation. A 56-year-old woman presented with worsening lower extremity weakness, imbalance, and difficulty ambulating. Strength was 3/5 in her right lower extremity and 4/5 in her left lower extremity. She had an incomplete T4 sensory level and hyperreflexia. Magnetic resonance imaging demonstrated a heterogeneous "popcorn"-appearing expansile intradural intramedullary 2.2- × 1.2-cm lesion at T4-5, consistent with a cavernous malformation. Angiography was deferred given the characteristic magnetic resonance imaging appearance. Given her progressive symptoms (including weakness), lesion size, and good health, resection was recommended. Using neurological monitoring, a T4-5 laminectomy, midline myelotomy, and piecemeal microsurgical resection of the lesion was performed, clearly identifying the cavernoma-spinal cord interface and avoiding spinal cord retraction. Histopathology confirmed a cavernoma. Postoperatively, the patient had improved left lower extremity strength and stable right lower extremity strength but worsened dorsiflexion (1/5), which improved with rehabilitation. At 1-year follow-up, she had full strength in her left lower extremity and 4/5 in her right lower extremity, with mild paresthesias below T10. Consistent with prior series demonstrating low complication rates and good long-term neurological outcomes,² microsurgical resection of selected symptomatic intramedullary spinal cavernous malformations can halt neurological decline and potentially improve neurological function.

Preoperative Magnetic Resonance Imaging Abnormalities Predict Symptomatic Adjacent Segment Degeneration After Anterior Cervical Discectomy and Fusion

Introduction

Anterior cervical discectomy and fusions (ACDFs) are generally limited to the levels causing neurological symptoms, but whether adjacent asymptomatic levels should be included if they demonstrate severe radiographic degeneration is a matter of controversy. We evaluated whether asymptomatic preoperative magnetic resonance imaging (MRI) abnormalities at adjacent levels were predictive of reoperation for symptomatic adjacent-segment degeneration (ASD) after the initial ACDF.

Methods

We reviewed patients treated with ACDF in 2000-2010 who had MRIs preoperatively and again ≥3 years after the index surgery to evaluate new neurological symptoms. Patients were stratified by ASD severity score, calculated based on MRI features. The associations between preoperative ASD severity score and reoperation for ASD were evaluated with logistic and Cox regressions after adjusting for covariates.

Results

Of 1038 patients who underwent ACDF, 96 (9%) had MRI evaluation ≥3 years postoperatively (mean follow-up 78 months). Of the 195 adjacent segments evaluated, 14 (7%) were included in subsequent fusion procedures. The 10-year surgery-free survival estimate was 82.7% (73.4-93.2%). After adjusting for covariates, ASD severity scores were predictive of reoperation only for patients with the highest score (hazard ratio [HR] 4.5 [1.0-19.8]) and those with foraminal stenosis (HR 4.2 [.4-12.7]). However, the prevalence of reoperation for ASD in these groups was only 16% and 15%, respectively.

Conclusion

The prevalence of reoperation for ASD was low for patients who presented with new symptoms ≥3 years after the index ACDF. Our findings do not support including asymptomatic levels in an anterior fusion construct, even if severe MRI abnormalities are present preoperatively.

Kickstand Rod Technique for Correcting Coronal Imbalance in Adult Scoliosis: 2-Dimensional Operative Video

Restoration of spinal alignment and balance is a major goal of adult scoliosis surgery. In the past, sagittal alignment has been emphasized and was shown to have the greatest impact on functional outcomes. However, recent evidence suggests the impact of coronal imbalance on pain and functional outcomes has likely been underestimated.1,2 In addition, iatrogenic coronal imbalance may be common and frequently results from inadequate correction of the lumbosacral fractional curve.2,3 The "kickstand rod" is a recently described technique to achieve and maintain significant coronal-plane correction.4 Also, of secondary benefit, the kickstand rod may function as an accessory supplemental rod to offload stress and bolster primary instrumentation. This may reduce occurrence of rod fracture (RF) or pseudarthrosis (PA).5  Briefly, this technique involves positioning the kickstand rod on the side of coronal imbalance (along the major curve concavity or fractional curve convexity in our video demonstration). The kickstand rod spans the thoracolumbar junction proximally to the pelvis distally and is secured with an additional iliac screw placed just superior to the primary iliac screw. By using the iliac wing as a base, powerful distraction forces can reduce the major curve to achieve more normal coronal balance. This operative video illustrates the technical nuances of utilizing the kickstand rod technique for correction of severe lumbar scoliosis and coronal malalignment in a 60-yr-old male patient. Alignment correction was achieved and maintained without evidence of RF/PA after nearly 6 mo postoperatively. The patient gave informed consent for surgery and to use imaging for medical publication.

Clinical Effectiveness of S2-Alar Iliac Screws in Spinopelvic Fixation in Pediatric Neuromuscular Scoliosis: Systematic Literature Review

STUDY DESIGN

Systematic literature review.

OBJECTIVES

To comprehensively review the S2-alar iliac (S2-AI) screw technique for pelvic fixation in pediatric neuromuscular scoliosis.

METHODS

Articles identified from the PubMed and EMBASE databases were reviewed for relevance and applicability, and the studies were summarized.

RESULTS

Eight articles met the inclusion criteria. A total of 277 pediatric patients underwent spinopelvic fixation using S2-AI fixation for neuromuscular scoliosis; the mean follow-up was 3 years (range = 0.75-6 years). Six articles had level III evidence (5 retrospective cohort studies, 1 observational study), and 2 articles had level IV evidence (case series). Wound complications occurred in 34 (12.2%) patients. Instrumentation complications occurred in 36 patients (13.0%), including lucency around the screw (6.5%), screw fracture (3.6%), disengaging of the set/screw or rod from the tulip head (2.8%), and screw displacement (0.7%). Three patients (1.1%) required reoperation for instrumentation failures. The overall reoperation rate-including 3 hardware replacements and 3 cases of L5-S1 pseudarthrosis-was 2.1%. The mean Cobb angle correction was 51.4°, and the mean pelvic obliquity correction was 14.8°; deformity correction was maintained at 3- and 5-year follow-ups. There were 10 (3.6%) cases of implant prominence/implant-related pain, 1 case of sacroiliac joint pain (resolved with longer screw placement), and no major neurological or vascular complications secondary to S2-AI screw placement.

CONCLUSIONS

This review suggests that the use of S2-AI screws in pediatric neuromuscular scoliosis is efficacious with a reasonable safety profile and provides a useful technique for pelvic fixation in children with scoliosis.

Restabilization of the Occipitocervical Junction After a Complete Unilateral Condylectomy: A Biomechanical Comparison of Unilateral and Bilateral Fixation Techniques

BACKGROUND

Occipitocervical instability may result from transcondylar resection of the occipital condyle. Initially, patients may be able to maintain a neutral alignment but severe occipitoatlantal subluxation may subsequently occur, with cranial settling, spinal cord kinking, and neurological injury.

OBJECTIVE

To evaluate the ability of posterior fixation constructs to prevent progression to severe deformity after radical unilateral condylectomy.

METHODS

Eight human cadaveric specimens (Oc-C2) underwent biomechanical testing to compare stiffness under physiological loads (1.5 N m). A complete unilateral condylectomy was performed to destabilize one Oc-C1 joint, and the contralateral joint was left intact. Unilateral Oc-C1 or Oc-C2 constructs on the resected side and bilateral Oc-C1 or Oc-C2 constructs were tested.

RESULTS

The bilateral Oc-C2 construct provided the greatest stiffness, but the difference was only statistically significant in certain planes of motion. The unilateral constructs had similar stiffness in lateral bending, but the unilateral Oc-C1 construct was less stiff in axial rotation and flexion-extension than the unilateral Oc-C2 construct. The bilateral Oc-C2 construct was stiffer than the unilateral Oc-C2 construct in axial rotation and lateral bending, but there was no difference between these constructs in flexion-extension.

CONCLUSION

Patients who undergo a complete unilateral condylectomy require close surveillance for occipitocervical instability. A bilateral Oc-C2 construct provides suitable biomechanical strength, which is superior to other constructs. A unilateral construct decreases abnormal motion but lacks the stiffness of a bilateral construct. However, given that most patients undergo a partial condylectomy and only a small proportion of patients develop instability, there may be scenarios in which a unilateral construct may be appropriate, such as for temporary internal stabilization.

Rotational thromboelastometry-guided transfusion during lumbar pedicle subtraction osteotomy for adult spinal deformity: preliminary findings from a matched cohort study

OBJECTIVESignificant blood loss and coagulopathy are often encountered during adult spinal deformity (ASD) surgery, and the optimal intraoperative transfusion algorithm is debatable. Rotational thromboelastometry (ROTEM), a functional viscoelastometric method for real-time hemostasis testing, may allow early identification of coagulopathy and improve transfusion practices. The objective of this study was to investigate the effect of ROTEM-guided blood product management on perioperative blood loss and transfusion requirements in ASD patients undergoing correction with pedicle subtraction osteotomy (PSO).METHODSThe authors retrospectively reviewed patients with ASD who underwent single-level lumbar PSO at the University of Virginia Health System. All patients who received ROTEM-guided blood product transfusion between 2015 and 2017 were matched in a 1:1 ratio to a historical cohort treated using conventional laboratory testing (control group). Co-primary outcomes were intraoperative estimated blood loss (EBL) and total blood product transfusion volume. Secondary outcomes were perioperative transfusion requirements and postoperative subfascial drain output.RESULTSThe matched groups (ROTEM and control) comprised 17 patients each. Comparison of matched group baseline characteristics demonstrated differences in female sex and total intraoperative dose of intravenous tranexamic acid (TXA). Although EBL was comparable between ROTEM versus control (3200.00 ± 2106.24 ml vs 3874.12 ± 2224.22 ml, p = 0.36), there was a small to medium effect size (Cohen's d = 0.31) on EBL reduction with ROTEM. The ROTEM group had less total blood product transfusion volume (1624.18 ± 1774.79 ml vs 2810.88 ± 1847.46 ml, p = 0.02), and the effect size was medium to large (Cohen's d = 0.66). This difference was no longer significant after adjusting for TXA (β = -0.18, 95% confidence interval [CI] -1995.78 to 671.64, p = 0.32). More cryoprecipitate and less fresh frozen plasma (FFP) were transfused in the ROTEM group patients (cryoprecipitate units: 1.24 ± 1.20 vs 0.53 ± 1.01, p = 0.03; FFP volume: 119.76 ± 230.82 ml vs 673.06 ± 627.08 ml, p < 0.01), and this remained significant after adjusting for TXA (cryoprecipitate units: β = 0.39, 95% CI 0.05 to 1.73, p = 0.04; FFP volume: β = -0.41, 95% CI -772.55 to -76.30, p = 0.02). Drain output was lower in the ROTEM group and remained significant after adjusting for TXA.CONCLUSIONSFor ASD patients treated using lumbar PSO, more cryoprecipitate and less FFP were transfused in the ROTEM group compared to the control group. These preliminary findings suggest ROTEM-guided therapy may allow early identification of hypofibrinogenemia, and aggressive management of this may reduce blood loss and total blood product transfusion volume. Additional prospective studies of larger cohorts are warranted to identify the appropriate subset of ASD patients who may benefit from intraoperative ROTEM analysis.

Multicenter Study of Pipeline Flex for Intracranial Aneurysms

BACKGROUND

The Pipeline Flex (PED Flex; Medtronic, Dublin, Ireland) was designed to facilitate deployment and navigation compared to its previous iteration to reduce the rate of technical events and complications.

OBJECTIVE

To assess the neurological morbidity and mortality rates of the PED Flex at 30 d.

METHODS

Information from 9 neurovascular centers was retrospectively obtained between July 2014 and March 2016. Data included patient/aneurysm characteristics, periprocedural events, clinical, and angiographic outcomes. Multivariate logistic regression was performed to determine predictors of unfavorable clinical outcome (modified Rankin Scale [mRS] > 2).

RESULTS

A total of 205 patients harboring 223 aneurysms were analyzed. The 30-d neurological morbidity and mortality rates were 1.9% (4/205) and 0.5% (1/205), respectively. The rate of intraprocedural events without neurological morbidity was 6.8% (14/205), consisting of intraprocedural ischemic events in 9 patients (4.5%) and hemorrhage in 5 (2.4%). Other technical events included difficulty capturing the delivery wire in 1 case (0.5%) and device migration after deployment in another case (0.5%). Favorable clinical outcome (mRS 0-2) was achieved in 186 patients (94.4%) at discharge and in 140 patients (94.5%) at 30 d. We did not find predictors of clinical outcomes on multivariate analysis.

CONCLUSION

The 30-d rates of neurological morbidity and mortality in this multicenter cohort using the PED Flex for the treatment of intracranial aneurysms were low, 1.9% (4/205) and 0.5% (1/205), respectively. In addition, technical events related to device deployment were also low, most likely due to the latest modifications in the delivery system.

Unique Far-Lateral Closure Technique: Technical Note

BACKGROUND

The far-lateral approach is a mainstay in gaining access to the ventrolateral craniocervical junction for tumor removal and the treatment of vascular lesions. It has a reportedly high rate of cerebrospinal fluid leak (up to 20%), which can bring devastating consequences, including meningitis, and may require wound revision associated with a longer hospital stay.

OBJECTIVE

To describe a closure technique employed to close the access corridor provided by the far-lateral approach and present an illustrative case.

METHODS

The far-lateral closure technique employs dural closure, followed by fat buttress, to alleviate dead space and reduce the likelihood of fluid collection and leakage.

RESULTS

This technique has been successfully used by the senior author for more than 14 yr, with a rate of cerebrospinal fluid leak of 2.9%.

CONCLUSION

This unique approach and closure of the far-lateral craniotomy is a reasonable option for the approach to the ventrolateral craniocervical junction. Skull base surgeons can consider the use of this closure technique to ensure watertight closure.

Minimally invasive oblique interbody fusion for correction of iatrogenic lumbar deformity

Spinal instability may arise as a consequence of decompressive lumbar surgery. An oblique lumbar interbody fusion combined with pedicle screw fixation can provide indirect decompression on neural elements, stabilization of mobile spondylolisthesis, and restoration of segmental lordosis. Minimally invasive techniques may facilitate a shorter hospitalization and faster recovery than a traditional open revision operation. The authors describe the use of an anterior interbody fusion via an oblique retroperitoneal approach and posterior pedicle screw fixation to treat a 67-year-old woman who developed L3–4 and L4–5 unstable spondylolisthesis after a lumbar laminectomy.

The video can be found here: https://youtu.be/KWwGMIoDrmU.

Emergent Reversal of Direct Oral Anticoagulants Permitting Neurosurgical Intervention for Nonhemorrhagic Pathology

BACKGROUND

Direct oral anticoagulants (DOACs) are becoming the medication of choice for the management of venous thromboembolism and stroke prevention in atrial fibrillation because of simplified dosing, a more predictive pharmacokinetic profile, and better clinical outcomes when compared with traditional vitamin K antagonists. Recently, reversal agents for DOACs have been approved by the U.S. Food and Drug Administration for use in managing life-threatening or uncontrolled bleeding; however, for acute nonhemorrhagic conditions requiring surgical intervention, such as acute hydrocephalus requiring ventriculostomy, there is little evidence to help guide appropriate management for patients on DOACs.

CASE DESCRIPTION

We report the use of andexanet alfa to counteract rivaroxaban treatment in a 28-year-old woman who developed herniation syndrome and acute hydrocephalus from a cerebellar tumor.

CONCLUSIONS

We describe how appropriate timing of administration of the DOAC reversal agent may permit urgent neurosurgical intervention.

A Case of Ventral Spinal Cord Herniation from a Chronic Dural-pleural Fistula Resulting in Thoracic Myelopathy

Formation of a dural-pleural fistula is uncommon after anterior thoracic spine surgery, tumor, or trauma. The goal of surgical management is to terminate the connection between the pleura and subarachnoid space. We describe a case of chronic dural-pleural fistula in a 70-year-old woman and present a unique surgical treatment option. The patient presented 25 years after an anterior thoracic surgery she had undergone for a thoracic disc herniation, with a dural-pleural fistula and ventral herniation of the spinal cord into the defect. She was treated with a bovine pericardium sling patch to cover the defect. This case highlights the identification of a chronic thoracic dural-pleural fistula and surgical treatment with double intradural and extradural layering of bovine pericardium sling patch, which has not been described previously for chronic thoracic dural-pleural fistula.

Radiographic outcome and complications after single-level lumbar extended pedicle subtraction osteotomy for fixed sagittal malalignment: a retrospective analysis of 55 adult spinal deformity patients with a minimum 2-year follow-up

OBJECTIVEFixed sagittal spinal malalignment is a common problem in adult spinal deformity (ASD). Various three-column osteotomy techniques, including the extended pedicle subtraction osteotomy (ePSO), may correct global and regional malalignment in this patient population. In contrast to the number of reports on traditional PSO (Schwab grade 3 osteotomy), there is limited literature on the outcomes of ePSO (Schwab grade 4 osteotomy) in ASD surgery. The objective of this retrospective study was to provide focused investigation of radiographic outcomes and complications of single-level lumbar ePSO for ASD patients with fixed sagittal malalignment.METHODSConsecutive ASD patients in whom sagittal malalignment had been treated with single-level lumbar ePSO at the authors' institution between 2010 and 2015 were analyzed, and those with a minimum 2-year follow-up were included in the study. Radiographic analyses included assessments of segmental lordosis through the ePSO site (sagittal Cobb angle measured from the superior endplate of the vertebra above and inferior endplate of the vertebra below the ePSO), lumbar lordosis (LL), pelvic tilt (PT), pelvic incidence and LL mismatch, thoracic kyphosis (TK), and sagittal vertical axis (SVA) on standing long-cassette radiographs. Complications were analyzed for the entire group.RESULTSAmong 71 potentially eligible patients, 55 (77%) had a minimum 2-year follow-up and were included in the study. Overall, the average postoperative increases in ePSO segmental lordosis and overall LL were 41° ± 14° (range 7°-69°, p < 0.001) and 38° ± 11° (range 9°-58°, p < 0.001), respectively. The average SVA improvement was 13 ± 7 cm (range of correction: -33.6 to 3.4 cm, p < 0.001). These measurements were maintained when comparing early postoperative to last follow-up values, respectively (mean follow-up 52 months, range 26-97 months): ePSO segmental lordosis, 34° vs 33°, p = 0.270; LL, 47.3° vs 46.7°, p = 0.339; and SVA, 4 vs 5 cm, p = 0.330. Rod fracture (RF) at the ePSO site occurred in 18.2% (10/55) of patients, and pseudarthrosis (PA) at the ePSO site was confirmed by CT imaging or during rod revision surgery in 14.5% (8/55) of patients. Accessory supplemental rods across the ePSO site, a more recently employed technique, significantly reduced the occurrence of RF or PA on univariate (p = 0.004) and multivariable (OR 0.062, 95% CI 0.007-0.553, p = 0.013) analyses; this effect approached statistical significance on Kaplan-Meier analysis (p = 0.053, log-rank test). Interbody cage placement at the ePSO site resulted in greater ePSO segmental lordosis correction (45° vs 35°, p = 0.007) without significant change in RF or PA (p = 0.304). Transient and persistent motor deficits occurred in 14.5% (8/55) and 1.8% (1/55) of patients, respectively.CONCLUSIONSExtended PSO is an effective technique to correct fixed sagittal malalignment for ASD. In comparison to traditional PSO techniques, ePSO may allow greater focal correction with comparable complication rates, especially with interbody cage placement at the ePSO site and the use of accessory supplemental rods.

Delayed Occipitocervical Instability With Cranial Settling After Far-Lateral Transcondylar Surgery for Invasive Skull Base Tumor

BACKGROUND

Occipitocervical instability is a rare but potentially severe complication of a far-lateral transcondylar surgical approach to the skull base.

OBJECTIVE

To investigate the incidence of clinically significant occipitocervical instability after transcondylar surgery via a far-lateral approach and to determine whether the extent of occipital condyle resection relative to the hypoglossal canal was associated with the development of occipitocervical instability.

METHODS

A retrospective review of patients undergoing far-lateral transcondylar surgery was performed at our institution to identify patients who developed postoperative occipitocervical instability.

RESULTS

Of the 61 far-lateral transcondylar operations performed, the authors identified 2 cases of delayed occipitocervical instability after surgery. In each case, the patient had tumor invading into the occipital condyle and supracondylar region and a resection extending anterior to the hypoglossal canal was performed. Both patients presented with pathological fractures and a severe occipitocervical deformity.

CONCLUSION

Patients who have tumor involvement of the occipital condyle and supracondylar region and undergo partial unilateral condylar resection are at risk for occipitocervical instability and should be considered for occipitocervical fusion.

Low rates of complications after spinopelvic fixation with iliac screws in 260 adult patients with a minimum 2-year follow-up

OBJECTIVERecent literature describing complications associated with spinopelvic fixation with iliac screws in adult patients has been limited but has suggested high complication rates. The authors' objective was to report their experience with iliac screw fixation in a large series of patients with a 2-year minimum follow-up.METHODSOf 327 adult patients undergoing spinopelvic fixation with iliac screws at the authors' institution between 2010 and 2015, 260 met the study inclusion criteria (age ≥ 18 years, first-time iliac screw placement, and 2-year minimum follow-up). Patients with active spinal infection were excluded. All iliac screws were placed via a posterior midline approach using fluoroscopic guidance. Iliac screw heads were deeply recessed into the posterior superior iliac spine. Clinical and radiographic data were obtained and analyzed.RESULTSTwenty patients (7.7%) had iliac screw-related complication, which included fracture (12, 4.6%) and/or screw loosening (9, 3.5%). No patients had iliac screw head prominence that required revision surgery or resulted in pain, wound dehiscence, or poor cosmesis. Eleven patients (4.2%) had rod or connector fracture below S1. Overall, 23 patients (8.8%) had L5-S1 pseudarthrosis. Four patients (1.5%) had fracture of the S1 screw. Seven patients (2.7%) had wound dehiscence (unrelated to the iliac screw head) or infection. The rate of reoperation (excluding proximal junctional kyphosis) was 17.7%. On univariate analysis, an iliac screw-related complication rate was significantly associated with revision fusion (70.0% vs 41.2%, p = 0.013), a greater number of instrumented vertebrae (mean 12.6 vs 10.3, p = 0.014), and greater postoperative pelvic tilt (mean 27.7° vs 23.2°, p = 0.04). Lumbosacral junction-related complications were associated with a greater mean number of instrumented vertebrae (12.6 vs 10.3, p = 0.014). Reoperation was associated with a younger mean age at surgery (61.8 vs 65.8 years, p = 0.014), a greater mean number of instrumented vertebrae (12.2 vs 10.2, p = 0.001), and longer clinical and radiological mean follow-up duration (55.8 vs 44.5 months, p < 0.001; 55.8 vs 44.6 months, p < 0.001, respectively). On multivariate analysis, reoperation was associated with longer clinical follow-up (p < 0.001).CONCLUSIONSPrevious studies on iliac screw fixation have reported very high rates of complications and reoperation (as high as 53.6%). In this large, single-center series of adult patients, iliac screws were an effective method of spinopelvic fixation that had high rates of lumbosacral fusion and far lower complication rates than previously reported. Collectively, these findings argue that iliac screw fixation should remain a favored technique for spinopelvic fixation.

Extended Asymmetrical Pedicle Subtraction Osteotomy for Adult Spinal Deformity: 2-Dimensional Operative Video

Pedicle subtraction osteotomy (PSO) is an effective technique to correct fixed sagittal malalignment. A variation of this technique, the “trans-discal” or “extended” PSO (Schwab grade IV osteotomy), involves extending the posterior wedge resection of the index vertebra to include the superior adjacent disc for radical discectomy. The posterior wedge may be resected in asymmetric fashion to correct concurrent global coronal malalignment.

This video illustrates the technical nuances of an extended asymmetrical lumbar PSO for adult spinal deformity. A 62-yr-old female with multiple prior lumbar fusions presented with worsening back pain and posture. Preoperative scoliosis X-rays demonstrated severe global sagittal and coronal malalignment (sagittal vertical axis [SVA, C7-plumbline] of 13.5 cm, pelvic incidence [PI] of 60°, lumbar lordosis [LL] of 14° [in kyphosis], pelvic tilt [PT] of 61°, thoracic kyphosis [TK] of 18°, and rightward coronal shift of 9.3 cm). The patient gave informed consent to surgery and for use of her imaging for medical publication. Briefly, surgery first involved transpedicular instrumentation from T10 to S1 with bilateral iliac screw fixation, and then T11-12 and T12-L1 Smith-Petersen osteotomies were performed. Next, an extended asymmetrical L4 PSO was performed and a 12° lordotic cage (9 × 14 × 40 mm) was placed at the PSO defect. Rods were placed from T10 to iliac bilaterally, and accessory supplemental rods spanning the PSO were attached. Postoperative scoliosis X-rays demonstrated improved alignment: SVA 5.5 cm, PI 60°, LL 55°, PT 36°, TK 37°, and 3.7 cm of rightward coronal shift. The patient had uneventful recovery.

A Novel Junctional Tether Weave Technique for Adult Spinal Deformity: 2-Dimensional Operative Video

Proximal junctional kyphosis (PJK) is a common problem after multilevel spine instrumentation for adult spinal deformity. Various anti-PJK techniques such as junctional tethers for ligamentous augmentation have been proposed. We present an operative video demonstrating technical nuances of junctional tether “weave” application. A 70-yr-old male with prior L2-S1 instrumented fusion presented with worsening back pain and posture. Imaging demonstrated pathological loss of lumbar lordosis (flat back deformity), proximal junctional failure, and pseudarthrosis. The patient had severe global and segmental sagittal malalignment, with sagittal vertical axis (SVA, C7-plumbline) measuring 22.3 cm, pelvic incidence (PI) 55°, lumbar lordosis (LL) 8° in kyphosis, pelvic tilt (PT) 30°, and thoracic kyphosis (TK) 6°. The patient gave informed consent for surgery and use of imaging for medical publication. Briefly, surgery first involved re-instrumentation with bilateral pedicle screws from T10 to S1. After right-sided iliac screw fixation (left-sided iliac screw fixation was not performed due to extensive prior iliac crest bone graft harvesting), we then completed a L2-3 Smith–Petersen osteotomy, extended L4 pedicle subtraction osteotomy, and L3-4 interbody arthrodesis with a 12° lordotic cage (9 × 14 × 40 mm). Cobalt Chromium rods were placed spanning the instrumentation bilaterally, and accessory supplemental rods spanning the PSO were attached. An anti-PJK junctional tether “weave” was then implemented using 4.5 mm polyethylene tape (Mersilene tape [Ethicon, Somerville, New Jersey]). Postoperative imaging demonstrated improved alignment (SVA 2.8 cm, PI 55°, LL 53°, PT 25°, TK 45°) and no significant neurological complications occurred during convalescence or at 6 mo postop.

Identifying Factors Predictive of Atlantoaxial Fusion Failure in Pediatric Patients: Lessons Learned From a Retrospective Pediatric Craniocervical Society Study

STUDY DESIGN

Multicenter retrospective cohort study with multivariate analysis.

OBJECTIVE

To determine factors predictive of posterior atlantoaxial fusion failure in pediatric patients.

SUMMARY OF BACKGROUND DATA

Fusion rates for pediatric posterior atlantoaxial arthrodesis have been reported to be high in single-center studies; however, factors predictive of surgical non-union have not been identified by a multicenter study.

METHODS

Clinical and surgical details for all patients who underwent posterior atlantoaxial fusion at seven pediatric spine centers from 1995 to 2014 were retrospectively recorded. The primary outcome was surgical failure, defined as either instrumentation failure or fusion failure seen on either plain x-ray or computed tomography scan. Multiple logistic regression analysis was undertaken to identify clinical and technical factors predictive of surgical failure.

RESULTS

One hundred thirty-one patients met the inclusion criteria and were included in the analysis. Successful fusion was seen in 117 (89%) of the patients. Of the 14 (11%) patients with failed fusion, the cause was instrumentation failure in 3 patients (2%) and graft failure in 11 (8%). Multivariate analysis identified Down syndrome as the single factor predictive of fusion failure (odds ratio 14.6, 95% confidence interval [3.7-64.0]).

CONCLUSION

This retrospective analysis of a multicenter cohort demonstrates that although posterior pediatric atlantoaxial fusion success rates are generally high, Down syndrome is a risk factor that significantly predicts the possibility of surgical failure.

LEVEL OF EVIDENCE

3.

Use of the Pipeline embolization device in the treatment of iatrogenic intracranial vascular injuries: a bi-institutional experience

OBJECTIVE Flow-diverting devices have been used for the treatment of complex intracranial vascular pathology with success, but the role of these devices in treating iatrogenic intracranial vascular injuries has yet to be clearly defined. Here, the authors report their bi-institutional experience with the use of the Pipeline embolization device (PED) for the treatment of iatrogenic intracranial vascular injuries. METHODS The authors reviewed a retrospective cohort of patients with iatrogenic injuries to the intracranial vasculature that were treated with the PED between 2012 and 2016. Data collection included demographic data, indications for treatment, number and sizes of PEDs used, and immediate and follow-up angiographic and clinical outcomes. RESULTS Four patients with a mean age of 47.5 years (range 18-63 years) underwent PED placement for iatrogenic vessel injuries. In 3 patients, the intracranial internal carotid artery (ICA) was injured during transnasal tumor resection. In 1 patient, a basilar apex injury occurred during endoscopic third ventriculostomy. Three patients had a pseudoaneurysm as a result of vessel injury, and 1 patient had frank ICA laceration and extravasation. All 3 pseudoaneurysms were successfully treated with PED deployment. The ICA laceration was refractory to PED placement, and the vessel was subsequently occluded endovascularly. All 4 patients had a good clinical outcome (modified Rankin Scale score of 0 or 1). CONCLUSIONS The use of the PED is feasible in the management of iatrogenic pseudoaneurysms of the intracranial vasculature. In cases of frank vessel perforation, an alternative strategy such as covered stent placement should be considered. Endovascular or surgical vessel occlusion remains the definitive treatment in cases of refractory hemorrhage.

Flow diversion of tandem cerebral aneurysms: a multi-institutional retrospective study

OBJECTIVE Flow diversion has proven to be an efficacious means of treating cerebral aneurysms that are refractory to other therapeutic means. Patients with tandem aneurysms treated with flow diversion have been included in larger, previously reported series; however, there are no dedicated reports on using this technique during a single session to treat this unique subset of patients. Therefore, the authors analyzed the outcomes of patients who had undergone single-session flow diversion for the treatment of tandem aneurysms. METHODS The authors conducted a retrospective review of flow diversion with the Pipeline embolization device (PED) for the treatment of tandem aneurysms in a single session at 2 participating medical centers: University of Utah, Salt Lake City, Utah, and Barrow Neurological Institute, Phoenix, Arizona. Patient demographic data, aneurysm characteristics, treatment strategy and results, complications, and follow-up data were collected from the medical record and analyzed. RESULTS Between January 2011 and December 2015, 17 patients (12 female, 5 male) with a total of 38 aneurysms (mean size 4.7 ± 2.7 mm, mean ± SD) were treated. Sixteen patients had aneurysms in the anterior circulation, and 1 patient had tandem aneurysms in the posterior circulation. Twelve patients underwent only placement of a PED, whereas 5 underwent adjunctive coil embolization of at least 1 aneurysm. One PED was used in each of 9 patients, and 2 PEDs were required in each of 8 patients. There were 2 intraprocedural complications; however, in both instances, the patients were asymptomatic at the last follow-up. The follow-up imaging studies were available for 15 patients at a mean of 7 months after treatment (216 days, range 0-540 days). The mean initial Raymond score after treatment was 2.7 ± 0.7, and the mean final score was 1.3 ± 0.7. CONCLUSIONS In this series, the use of flow diversion for the treatment of tandem cerebral aneurysms had an acceptable safety profile, indicating that it should be considered as an effective therapy for this complicated subset of patients. Further prospective studies must be performed before more definitive conclusions can be made.

Contemporary endovascular and open aneurysm treatment in the era of flow diversion

Clinical outcomes have improved considerably over the last decade for patients with ruptured and unruptured aneurysms. Modern endovascular techniques, such as flow diversion, are associated with high aneurysm occlusion rates and have become a popular treatment modality for many types of aneurysms. However, the safety and effectiveness of flow diversion has not yet been established in trials comparing it with traditional aneurysm treatments. Moreover, there are some types of aneurysms that may not be appropriate for endovascular coiling, such as wide-necked aneurysms located at branch points of major vessels, large saccular aneurysms with multiple efferent arteries, dolichoectatic aneurysms, large aneurysms with mass effect, when there are technical complications with endovascular treatment, when patients cannot tolerate or have contraindications to antiplatelet therapy or in the setting of a subarachnoid haemorrhage. For these cases, open cerebrovascular surgery remains important. This review provides a discussion on the current trends and evidence for both flow diversion and open cerebrovascular surgery for complex aneurysms that may not be suitable for coiling. We emphasise a continued important role for surgical treatment in certain situations.

The Use of Semitranslucent Rubber Pledgets During Microsurgical Dissection of Cerebellopontine Angle Tumors: Technical Note

BACKGROUND AND IMPORTANCE

Dissection of cerebellopontine angle (CPA) tumors that abut or adhere to the brainstem or cranial nerves can be a challenging surgical endeavor. We describe the use of semitranslucent latex rubber pledgets in the tumor-brain interface as a method to improve visualization and protection of vital tissue during microsurgical dissection of CPA masses. The rubber pledgets are fashioned by cutting circular discs out of the cuff portion of talc-free, partially opaque latex gloves. These pledgets provide a semitranslucent, nonadherent membrane that can be placed between vital neural tissues and a tumor capsule to minimize trauma during dissection. The semitranslucent latex enables visualization of the underlying anatomical structures while also providing a protective surface onto which a suction device can be rested to facilitate clearance of the surgical field.

CLINICAL PRESENTATION

A 56-yr-old woman with left ear tinnitus presented with a 3-cm CPA meningioma. During microsurgical dissection, rubber pledgets were used to preserve the interface between the brain stem, cranial nerves, and tumor capsule. The use of the rubber pledgets appeared to secure the interface between to tumor and the brain while at the same time protecting the cranial nerves, brainstem, and cerebellum.

CONCLUSION

Semitranslucent rubber pledgets may facilitate microsurgical dissection of CPA tumors.

Rerupture of a Blister Aneurysm After Treatment With a Single Flow-Diverting Stent

BACKGROUND AND IMPORTANCE

As the use of flow-diverting stents (FDSs) for intracranial aneurysms expands, a small number of case reports have described the successful treatment of blister aneurysms of the internal carotid artery with flow diversion. Blister aneurysms are uncommon and fragile lesions that historically have high rates of morbidity and mortality despite multiple treatment strategies. We report a case of rebleeding after treatment of a ruptured blister aneurysm with deployment of a single FDS.

CLINICAL PRESENTATION

A 29-year-old man presented with subarachnoid hemorrhage and a ruptured dorsal variant internal carotid artery aneurysm. Despite a technically successful treatment with a single FDS, a second catastrophic hemorrhage occurred during the course of his hospitalization.

CONCLUSION

This case highlights the risk of hemorrhage during the period after deployment of a single FDS. Ruptured aneurysms, especially of the blister type, are at risk for rehemorrhage while the occlusion remains incomplete after flow diversion.

ABBREVIATIONS

FDS, flow-diverting stentICA, internal carotid arterySAH, subarachnoid hemorrhage.

Fate of S2-Alar-Iliac Screws After 12-Month Minimum Radiographic Follow-up: Preliminary Results

BACKGROUND

S2-alar-iliac (S2AI) screws are 1 technique for lumbopelvic fixation to improve fusion rates across the lumbosacral junction that has gained wider acceptance. The S2AI screw crosses the cortical surfaces of the sacroiliac joint (SIJ), which may improve the biomechanical strength of the instrumentation.

OBJECTIVE

To report preliminary radiographic outcomes of patients who underwent lumbopelvic fixation with S2AI screws with a minimum 12-month follow-up.

METHODS

We retrospectively reviewed adult patients who underwent lumbopelvic fixation with S2AI screws. Patients with computed tomography (CT) scans obtained preoperatively and ≥12 months postoperatively were reviewed to determine whether there was S2AI screw backout or breakage, periscrew lucency, or SIJ degeneration, and to assess L5-S1 fusion status.

RESULTS

Twenty-six S2AI screws in 13 patients were evaluated (mean follow-up 24.8 months [14-52 months]). Nine patients had L5-S1 interbody grafts. Partial periscrew lucency was identified in 7 S2AI screws (27%) in 5 patients (38%), and L5-S1 fusion occurred in 92% of patients. L5-S1 nonunion was seen in 1 patient (8%), who had evidence of bilateral screw loosening in the sacral portion. Four patients with screw loosening had an osseous L5-S1 fusion. No patients had radiographic evidence of progression of SIJ degeneration, experienced screw backout or breakage, required reoperation for L5-S1 nonunion, or had S2AI screw-related complication.

CONCLUSION

S2AI screws maintained their integrity without causing SIJ degeneration or major screw-related complications in this small retrospective series with short follow-up. Long-term results are needed to evaluate the durability of S2AI screws over time.

Occipitocervical Instability After Far-Lateral Transcondylar Surgery: A Biomechanical Analysis

BACKGROUND

After a far-lateral transcondylar approach, patients may maintain neutral alignment in the immediate postoperative period, but severe occipitoatlantal subluxation may occur gradually with cranial settling and possible neurological injury. Previous research is based on assumptions regarding the extent of condylar resection and the change in biomechanics that produces instability.

OBJECTIVE

To quantify the extent of bone removal during a far-lateral transcondylar approach, determine the changes in range of motion (ROM) and stiffness that occur after condylar resection, and identify the threshold of condylar resection that predicts alterations in occipitocervical biomechanics.

METHODS

Nine human cadaveric specimens were biomechanically tested before and after far-lateral transcondylar resection extending into the hypoglossal canal (HC). The extent of condylar resection was quantified using volumetric comparison between pre- and postresection computed tomography scans. ROM and stiffness testing were performed in intact and resected states. The extent of resection that produced alterations in occipitocervical biomechanics was assessed with sensitivity analysis.

RESULTS

Bone removal during condylar resection into the HC was 15.4%-63.7% (mean 35.7%). Sensitivity analysis demonstrated that changes in biomechanics may occur when just 29% of the occipital condyle was resected (area under the curve 0.80-1.00).

CONCLUSION

Changes in occipitocervical biomechanics may be observed if one-third of the occipital condyle is resected. During surgery, the HC may not be a reliable landmark to guide the extent of resection. Patients who undergo condylar resections extending into or beyond the HC require close surveillance for occipitocervical instability.

Development and initial evaluation of a finite element model of the pediatric craniocervical junction

OBJECT There is a significant deficiency in understanding the biomechanics of the pediatric craniocervical junction (CCJ) (occiput-C2), primarily because of a lack of human pediatric cadaveric tissue and the relatively small number of treated patients. To overcome this deficiency, a finite element model (FEM) of the pediatric CCJ was created using pediatric geometry and parameterized adult material properties. The model was evaluated under the physiological range of motion (ROM) for flexion-extension, axial rotation, and lateral bending and under tensile loading. METHODS This research utilizes the FEM method, which is a numerical solution technique for discretizing and analyzing systems. The FEM method has been widely used in the field of biomechanics. A CT scan of a 13-month-old female patient was used to create the 3D geometry and surfaces of the FEM model, and an open-source FEM software suite was used to apply the material properties and boundary and loading conditions and analyze the model. The published adult ligament properties were reduced to 50%, 25%, and 10% of the original stiffness in various iterations of the model, and the resulting ROMs for flexion-extension, axial rotation, and lateral bending were compared. The flexion-extension ROMs and tensile stiffness that were predicted by the model were evaluated using previously published experimental measurements from pediatric cadaveric tissues. RESULTS The model predicted a ROM within 1 standard deviation of the published pediatric ROM data for flexion-extension at 10% of adult ligament stiffness. The model's response in terms of axial tension also coincided well with published experimental tension characterization data. The model behaved relatively stiffer in extension than in flexion. The axial rotation and lateral bending results showed symmetric ROM, but there are currently no published pediatric experimental data available for comparison. The model predicts a relatively stiffer ROM in both axial rotation and lateral bending in comparison with flexion-extension. As expected, the flexion-extension, axial rotation, and lateral bending ROMs increased with the decrease in ligament stiffness. CONCLUSIONS An FEM of the pediatric CCJ was created that accurately predicts flexion-extension ROM and axial force displacement of occiput-C2 when the ligament material properties are reduced to 10% of the published adult ligament properties. This model gives a reasonable prediction of pediatric cervical spine ligament stiffness, the relationship between flexion-extension ROM, and ligament stiffness at the CCJ. The creation of this model using open-source software means that other researchers will be able to use the model as a starting point for research.

BRCA2-positive spinal intramedullary ovarian metastatic disease: case report

BACKGROUND CONTEXT

Ovarian cancer is the fourth leading cause of cancer death in women, but advances in treatment have led to longer survival among these patients. Tied to these advances and increased survival, however, have been new patterns of metastatic spread.

PURPOSE

The authors discuss the management and surgical decision making in patients with intramedullary ovarian metastatic disease using a case illustration and relevant literature.

STUDY DESIGN/SETTING

A case report was used.

METHODS

The authors describe a case of a 59-year-old woman with Breast Cancer gene (BRCA) 2-positive ovarian cancer who developed progressive myelopathy from a T10 to T11 intramedullary metastatic lesion.

RESULTS

The patient underwent a standard open T10-T11 laminectomy for intramedullary tumor resection. Intraoperative ultrasound was used to direct the dural opening over the lesion. After a posterior midline myelotomy, microsurgical dissection revealed the intramedullary tumor with a discolored fibrous capsule, which was carefully dissected off of the spinal tracts, and a gross total resection was achieved. Postoperative magnetic resonance imaging at 6 months demonstrated no evidence of residual or recurrent intramedullary tumor. The patient underwent adjuvant external beam radiation to the thoracic spine but succumbed to her primary disease 1 year after surgery.

CONCLUSION

Although central nervous system involvement of ovarian cancer confers a poor prognosis, patients presenting with a solitary lesion and neurologic deficit may benefit from surgical resection followed by steroids and radiation therapy, especially when tissue diagnosis is necessary.

Inter-rater reliability of published flow diversion occlusion scales

Background

With increasing use of flow-diverting stents for the treatment of intracranial aneurysms, standardized methods and a common language to evaluate angiographic outcomes are needed. Multiple grading scales have been developed for this purpose but none has been widely adopted.

Objective

To analyze these scales to determine interobserver reliability.

Methods

Four independent assessors scored the intraprocedural angiograms of patients who underwent flow-diverting stent deployment for an intracranial saccular or fusiform aneurysm at our institution between October 2012 and June 2015. Angiographic outcome immediately after flow-diverting stent deployment was scored using three grading scales (Kamran–Byrne (KB), Simple Measurement of Aneurysm Residual after Treatment (SMART), and O'Kelley, Krings, Marotta (OKM)). Statistical analysis was performed using Light's κ for multiple raters (κ), Kendall's coefficient of concordance (W), and intraclass correlation (ICC).

Results

We included the angiograms of 50 consecutive patients (mean age 58 years, range 30–79) who underwent flow-diverting stent deployment for an intracranial aneurysm (40 saccular, 10 fusiform). Six aneurysms were located in the posterior circulation. The inter-rater reliability was typically poor or fair: SMART aneurysm filling (κ=0.30, W=0.36, ICC=0.12), SMART parent vessel stenosis (κ=0.07, W=0.33, ICC=0.12), KB axis I (κ=0.24, W=0.50, ICC=0.25), KB axis II (κ=0.07, W=0.30, ICC=0.06), OKM aneurysm filling (κ=0.23, W=0.45, ICC=0.13), OKM contrast stasis (κ=0.36,W=0.71, ICC=0.54).

Conclusions

Existing flow-diverting stent grading scales have low inter-rater reliability for most categories.

Patterns and Clinical Impact of Angiographically Visible Distal Emboli During Thrombectomy With Solitaire for Acute Ischemic Stroke

BACKGROUND:

Revascularization rates with stent retrievers after acute ischemic stroke are 69% to 86%, but favorable clinical outcomes occur in just 43% to 58% of cases. New distal emboli may negatively impact clinical outcomes.

OBJECTIVE:

To determine the prevalence and angiographic pattern of distal emboli associated with mechanical thrombectomy using the Solitaire Flow Restoration device and evaluate their correlation with clinical outcome.

METHODS:

We retrospectively reviewed the cerebral angiography of all patients with acute ischemic stroke who underwent mechanical thrombectomy with the use of the Solitaire FR device from 2012 to 2013. Angiographic microcatheter runs prior to Solitaire deployment and after thrombectomy were compared to identify new distal filling defects. Clinical outcome was assessed at discharge and after 90 days.

RESULTS:

Successful revascularization using the Solitaire device occurred in 36 of 39 patients (92%). Three distinct patterns were identified: new distal emboli in the same vascular territory (n = 3), new distal emboli in a new vascular territory (n = 3), and distal emboli that resolved after proximal revascularization (n = 7). Thirteen patients had distal emboli before and after Solitaire runs, and 13 showed no evidence of distal emboli. Favorable outcome (modified Rankin scores 0-2) was seen in 54% of all patients and 83% of patients with new distal emboli; thus, there was no correlation between new emboli and unfavorable clinical outcome (P = .67).

CONCLUSION:

We report an incidence rate of at least 15% of new emboli associated with use of the Solitaire device during thrombectomy in our series. Filling defects after Solitaire use were not associated with poor outcomes at discharge or 90-day follow-up.