The Postoperative Airway Compromise Score-First Steps to Developing a Postoperative Tool for the Assessment of Upper Airway-Related Complications Following Anterior Cervical Spine Surgery.

BACKGROUND: Acute upper airway compromise is a rare but catastrophic complication after anterior cervical discectomy and fusion. This study aims to develop a score to identify patients at risk of acute postoperative airway compromise (PAC). METHODS: Potential risk factors for acute PAC were selected by a modified Delphi process. Ten patients with acute PAC were identified of 1466 patients who underwent elective anterior cervical discectomy and fusion between July 2014 and May 2019. A comparison group was created by a randomized selection process (non-PAC group). Factors associated with PAC and a P value of < 0.10 were entered into a logistic regression model and coefficients contributed to each risk factor's overall score. Calibration of the model was evaluated using the Hosmer-Lemeshow goodness-of-fit test. Quantitative discrimination was calculated, and the final model was internally validated with bootstrap sampling. RESULTS: We identified 18 potential risk factors from our Delphi process, of which 6 factors demonstrated a significant association with airway compromise: age >65 years, current smoking status, American Society of Anesthesiologists class >2, history of a bleeding disorder, surgery of upper subaxial cervical spine (above C4), and duration of surgery >179 minutes. The final prediction model included 5 predictors with very strong performance characteristics. These 5 factors formed the PAC score, with a range from 0 to 100. A score of 20 yielded the greatest balance of sensitivity (80%) and specificity (88%). CONCLUSIONS: The acute PAC score demonstrates strong performance characteristics. The PAC score might help identify patients at risk of upper airway compromise caused by surgical site abnormalities.

A novel scoring system concept for de novo spinal infection treatment, the Spinal Infection Treatment Evaluation Score (SITE Score): a proof-of-concept study.

OBJECTIVE: De novo infections of the spine are an increasing healthcare problem. The decision for nonsurgical or surgical treatment is often made case by case on the basis of physician experience, specialty, or practice affiliation rather than evidence-based medicine. To create a more systematic foundation for surgical assessments of de novo spinal infections, the authors applied a formal validation process toward developing a spinal infection scoring system using principles gained from other spine severity scoring systems like the Spine Instability Neoplastic Score, Thoracolumbar Injury Classification and Severity Score, and AO Spine classification of thoracolumbar injuries. They utilized an expert panel and literature reviews to develop a severity scale called the "Spinal Infection Treatment Evaluation Score" (SITE Score). METHODS: The authors conducted an evidence-based process of combining literature reviews, extracting key elements from previous scoring systems, and obtaining iterative expert panel input while following a formal Delphi process. The resulting basic SITE scoring system was tested on selected de novo spinal infection cases and serially refined by an international multidisciplinary expert panel. Intra- and interobserver reliabilities were calculated using the intraclass correlation coefficient (ICC) and Fleiss' and Cohen's kappa, respectively. A receiver operating characteristic analysis was performed for cutoff value analysis. The predictive validity was assessed through cross-tabulation analysis. RESULTS: The conceptual SITE scoring system combines the key variables of neurological symptoms, infection location, radiological variables for instability and impingement of neural elements, pain, and patient comorbidities. Ten patients formed the first cohort of de novo spinal infections, which was used to validate the conceptual scoring system. A second cohort of 30 patients with de novo spinal infections, including the 10 patients from the first cohort, was utilized to validate the SITE Score. Mean scores of 6.73 ± 1.5 and 6.90 ± 3.61 were found in the first and second cohorts, respectively. The ICCs for the total score were 0.989 (95% CI 0.975-0.997, p < 0.01) in the first round of scoring system validation, 0.992 (95% CI 0.981-0.998, p < 0.01) in the second round, and 0.961 (95% CI 0.929-0.980, p < 0.01) in the third round. The mean intraobserver reliability was 0.851 ± 0.089 in the third validation round. The SITE Score yielded a sensitivity of 97.77% ± 3.87% and a specificity of 95.53% ± 3.87% in the last validation round for the panel treatment decision. CONCLUSIONS: The SITE scoring concept showed statistically meaningful reliability parameters. Hopefully, this effort will provide a foundation for a future evidence-based decision aid for treating de novo spinal infections. The SITE Score showed promising inter- and intraobserver reliability. It could serve as a helpful tool to guide physicians' therapeutic decisions in managing de novo spinal infections and help in comparison studies to better understand disease severity and outcomes.

Who Needs Surgical Stabilization for Pyogenic Spondylodiscitis? Retrospective Analysis of Non-Surgically Treated Patients.

STUDY DESIGN: Retrospective case series analysis. OBJECTIVE: To identify relevant clinical and radiographic markers for patients presenting with infectious spondylo-discitis associated with spinal instability directly related to the infectious process. METHODS: We evaluated patients presenting with de-novo intervertebral discitis or vertebral osteomyelitis /discitis (VOD) who initiated non-surgical treatment. Patients who failed conservative treatment and required stabilization surgery within 90 days were defined as "failed treatment group" (FTG). Patients who experienced an uneventful course served as controls and were labeled as "nonsurgical group" (NSG). A wide array of baseline clinical and radiographic parameters was retrieved and compared between 2 groups. RESULTS: Overall 35 patients had initiated non-surgical treatment for VOD. 25 patients had an uneventful course (NSG), while 10 patients failed conservative treatment ("FTG") within 90 days. Factors found to be associated with poorer outcome were intra-venous drug abuse (IVDA) as well as the presence of fever upon initial presentation. Radiographically, involvement of the same-level facets and the extent of caudal and rostral VB involvement in both MRI and CT were found to be significantly associated with poorer clinical and radiographic outcome. CONCLUSIONS: We show that clinical factors such as IVDA status and fever as well as the extent of osseous and posterior element involvement may prove to be helpful in favoring surgical treatment early on in the management of spinal infections.

A novel anatomo-physiologic high-grade spondylolisthesis model to evaluate L5 nerve stretch injury after spondylolisthesis reduction.

L5 nerve palsy is a well-known complication following reduction of high-grade spondylolisthesis. While several mechanisms for its occurrence have been proposed, the hypothesis of L5 nerve root strain or displacement secondary to mechanical reduction remains poorly studied. The aim of this cadaveric study is to determine changes in morphologic parameters of the L5 nerve root during simulated intraoperative reduction of high-grade spondylolisthesis. A standard posterior approach to the lumbosacral junction was performed in eight fresh-frozen cadavers with lumbosacral or lumbopelvic screw fixation. Wide decompressions of the spinal canal and L5 nerve roots with complete facetectomies were accomplished with full exposure of the L5 nerve roots. A 100% translational slip was provoked by release of the iliolumbar ligaments and cutting the disc with the attached anterior longitudinal ligament. To evaluate the path of the L5 nerves during reduction maneuvers, metal bars were inserted bilaterally at the inferomedial aspects of the L5 pedicle at a distance of 10 mm from the midpoint of the L5 pedicle screws. There was no measurable change in length of the L5 nerve roots after 50% and 100% reduction of spondylolisthesis. Mechanical strain or displacement during reduction is an unlikely cause of L5 nerve root injury. Further anatomical or physiological studies are necessary to explore alternative mechanisms of L5 nerve palsy in the setting of high-grade spondylolisthesis correction, and surgeons should favor extensive surgical decompression of the L5 nerve roots when feasible.

Surgical Treatment of Ossifications of the Cervical Anterior Longitudinal Ligament: A Retrospective Cohort Study.

STUDY DESIGN: Retrospective cohort study. OBJECTIVES: The study aims to evaluate anterior cervical discectomy and fusion (ACDF) in the treatment of patients with ossification of the anterior longitudinal ligament (OALL). METHODS: We retrospectively reviewed cases performed at our institution between January 2015 and December 2018; adult (age ≥18 years) patients who underwent anterior cervical decompression and fusion in the presence of dysphagia and OALL. Ten patients (9 male, 1 female, mean age 64.4 years) with OALL who underwent ACDF were included. Charts were reviewed for demographics and comorbidities. Primary outcomes assessed were intra- and postoperative complications. Secondary outcomes were fusion rates, instrumentation failure, postsurgical instability/deformity, and readmission rates. RESULTS: The average duration of symptoms prior to surgery was 12.3 months. All patients presented with dysphagia (mean Bazaz score 2.0). The average number of levels with OALL was 4.7 (±1.67). All patients underwent ACDF and 3 patients underwent additional posterior cervical fusion for kyphotic deformity correction or when extensive laminectomy was required. We did not encounter any intraoperative complications. Eight patients (72%) had solid fusion demonstrated on the lateral x-rays and no evidence of progressive kyphotic deformity. We did not encounter any instrumentation failure or loosening. Two patients developed recurrence of dysphagia (Bazaz scores 2 and 3 respectively). CONCLUSION: ACDF for OALL with dysphagia and concomitant myelopathy in our small series of 10 patients demonstrate good fusion and clinical outcomes. Larger studies will be necessary to determine the optimal treatment for patients with dysphagia due to OALL.

90-day Readmission Rates for Single Level Anterior Lumbosacral Interbody Fusion: A Nationwide Readmissions Database Analysis.

STUDY DESIGN: Nationwide Readmissions Database Study. OBJECTIVE: To investigate the patterns of readmissions and complications following hospitalization for elective single level anterior lumbobsacral interbody fusion. SUMMARY OF BACKGROUND DATA: Lumbar interbody spine fusions for degenerative disease have increased annually in the United States, including associated hospital costs. Anterior lumbar interbody fusions (ALIFs) have become popularized secondary to higher rates of fusion compared with posterior procedures, and preservation of posterior elements. Prior national databases have sought to study readmission rates with some limitations due to older diagnosis and procedure codes. The newer 2016 International Classification of Diseases Tenth Revision, Clinical Modification (ICD-10 CM) includes more specification of the surgical site. METHODS: We utilized the 2016 United States Nationwide Readmissions Database (NRD), this nationally representative, all-payer database that includes weighted probability sample of inpatient hospitalizations for all ages. We identified all adults (≥ 18 yrs) using the 2016 ICD-10 coding system who underwent elective primary L5-S1 ALIF and examined rates of readmissions within 90 days of discharge. RESULTS: Between January and September 2016, a total of 7029 patients underwent elective stand-alone L5-S1 ALIF who were identified from NRD of whom 497 (7.07%) were readmitted within 90 days of their procedure. No differences in sex were appreciated. Medicare patients had statistically significant higher readmission rates (47.69%) among all payer types. With respect to intraoperative complications, vascular complications had statistically significant increased odds of readmission (OR, 3.225, 95% CI, 0.59 -1.75; P = 0.0001). Readmitted patients had higher total healthcare costs. CONCLUSION: The 90-day readmission rate following stand-alone single level lumbosacral (L5-S1) ALIF was 7.07%. ALIF procedures have increased in frequency, and an understanding of the comorbidities, age-related demographics, and costs associated with 90-day readmissions are critical. Surgeons should consider these risk factors in preoperative planning and optimization. LEVEL OF EVIDENCE: 3.

Complications and Mortality in Octogenarians Undergoing Lumbopelvic Fixation.

BACKGROUND: Advancements in modern medicine have led to longer life expectancy. Literature on spinopelvic fixation in elderly patients is limited. We investigated morbidity and mortality in octogenarians who underwent spinopelvic fixation. METHODS: A retrospective chart review was conducted of patients who underwent spinopelvic fixation from January 2014 through December 2018 at a single institution. Patients were grouped into the octogenarian group (OG), 80-89 years old, and comparison group (CG), 40-50 years old. Demographics; pathology; Charlson Comorbidity Index; Hounsfield units; surgery details; and clinical data including complications, intensive care unit and length of hospital stay, and mortality were collected and compared. RESULTS: Inclusion criteria were met by 26 patients (OG: n = 14; CG: n = 12). Diagnoses in the OG were deformity (42.9%), pseudarthrosis (35.7%), fracture (7.1%), infection (7.1%), and tumor (7.1%). The only significant differences in baseline patient characteristics were that Charlson Comorbidity Index was significantly higher in the OG (6.0 ± 1.4) compared with the CG (1.1 ± 1.0) (P < 0.001) and the OG had lower Hounsfield units (P < 0.001), indicating poorer bone quality. More patients in the CG underwent staged and anterior approaches compared with the OG (P = 0.031). Major and minor complication rates were 57.1% and 42.9%, respectively, in the OG (P = 0.98) and 25% and 25% in the CG (P = 0.34). Mortality rate was 14.3%. CONCLUSIONS: With an aging population, the number of patients requiring spinopelvic fixation will continue to grow. Spine surgeons must carefully weigh benefits and risks in patients with multiple comorbidities.

When the air hits your brain: decreased arterial pulsatility after craniectomy leading to impaired glymphatic flow.

OBJECTIVECranial neurosurgical procedures can cause changes in brain function. There are many potential explanations, but the effect of simply opening the skull has not been addressed, except for research into syndrome of the trephined. The glymphatic circulation, by which CSF and interstitial fluid circulate through periarterial spaces, brain parenchyma, and perivenous spaces, depends on arterial pulsations to provide the driving force for bulk flow; opening the cranial cavity could dampen this force. The authors hypothesized that a craniectomy, without any other pathological insult, is sufficient to alter brain function due to reduced arterial pulsatility and decreased glymphatic flow. Furthermore, they postulated that glymphatic impairment would produce activation of astrocytes and microglia; with the reestablishment of a closed cranial compartment, the glymphatic impairment, astrocytic/microglial activation, and neurobehavioral decline caused by opening the cranial compartment might be reversed.METHODSUsing two-photon in vivo microscopy, the pulsatility index of cortical vessels was quantified through a thinned murine skull and then again after craniectomy. Glymphatic influx was determined with ex vivo fluorescence microscopy of mice 0, 14, 28, and 56 days following craniectomy or cranioplasty; brain sections were immunohistochemically labeled for GFAP and CD68. Motor and cognitive performance was quantified with rotarod and novel object recognition tests at baseline and 14, 21, and 28 days following craniectomy or cranioplasty.RESULTSPenetrating arterial pulsatility decreased significantly and bilaterally following unilateral craniectomy, producing immediate and chronic impairment of glymphatic CSF influx in the ipsilateral and contralateral brain parenchyma. Craniectomy-related glymphatic dysfunction was associated with an astrocytic and microglial inflammatory response, as well as with the development of motor and cognitive deficits. Recovery of glymphatic flow preceded reduced gliosis and return of normal neurological function, and cranioplasty accelerated this recovery.CONCLUSIONSCraniectomy causes glymphatic dysfunction, gliosis, and changes in neurological function in this murine model of syndrome of the trephined.

Fluid structure interaction model analysis of cerebrospinal fluid circulation in patients with continuous-flow left ventricular assist devices.

PURPOSE: The current 1-dimensional fluid structure interaction model (FSI) for understanding cerebrospinal fluid (CSF) circulation requires pulsatility as a precondition and has not been applied to patients with continuous-flow left ventricular assist devices (CF-LVAD) where pulsatility is chronically reduced. Our study aims to characterize the behavior of CSF pressure and flow in patients with CF-LVADs using a computational FSI model. METHODS: Utilizing the computational FSI model, CSF production in choroid plexuses of the 4 ventricles was specified as a boundary condition for the model. The other source of production from capillary ultrafiltrate spaces was accounted for by the mass conservation equation. The primary CSF absorption sites (i.e., arachnoid granulations) were treated as the outlet boundary conditions. We established a low pulse wave to represent patients with a CF-LVAD. RESULTS: From the model, low pulse conditions resulted in a reduction in CSF pressure amplitude and velocity though the overall flow rate was unchanged. CONCLUSIONS: The existing FSI model is not a suitable representation of CSF flow in CF-LVAD patients. More studies are needed to elucidate the role of pulsatility in CSF flow and the compensatory changes in CSF production and absorption that occur in patients with CF-LVADs in whom pulsatility is diminished.

Tree stand falls: A persistent cause of neurological injury in hunting.

AIM: To characterize and compare our current series of patients to prior reports in order to identify any changes in the incidence of neurological injury related to hunting accidents in Rochester, New York. METHODS: All tree stand-related injuries referred to our regional trauma center from September 2003 through November 2011 were reviewed. Information was obtained from the hospital's trauma registry and medical records were retrospectively reviewed for data pertaining to the injuries. RESULTS: Fifty-four patients were identified. Ninety-six percent of patients were male with a mean age of 47.9 years (range 15-69). The mean Injury Severity Score was 12.53 ± 1.17 (range 2-34). The average height of fall was 18.2 feet (range 4-40 feet). All patients fell to the ground with the exception of one who landed on rocks, and many hit the tree or branches on the way down. A reason for the fall was documented in only 13 patients, and included tree stand construction (3), loss of balance (3), falling asleep (3), structural failure (2), safety harness breakage (3) or light-headedness (1). The most common injuries were spinal fractures (54%), most commonly in the cervical spine (69%), followed by the thoracic (38%) and lumbar (21%) spine. Eight patients required operative repair. Head injuries occurred in 22%. Other systemic injuries include rib/clavicular fractures (47%), pelvic fractures (11%), solid organ injury (23%), and pneumothorax or hemothorax (19%). No patient deaths were reported. The average hospital length of stay was 6.56 ± 1.07 d. Most patients were discharged home without (72%) or with (11%) services and 17% required rehabilitation. CONCLUSION: Falls from hunting tree stands are still common, with a high rate of neurological injury. Compared to a decade ago we have made no progress in preventing these neurological injuries, despite an increase in safety advances. Neurosurgeons must continue to advocate for increased safety awareness and participate in leadership roles to improve outcomes for hunters.

Neurologic injury in snowmobiling.

BACKGROUND: Snowmobiles are increasingly popular recreational, all-terrain utility vehicles that require skill and physical strength to operate given their inherent maneuverability, acceleration, and top speed capabilities. These same characteristics increase the risk of injury with the operation of these vehicles, particularly neurological injury. We characterize our series of 107 patients involved in snowmobiling accidents. METHODS: From January 2004 to January 2012, all snowmobiling-related injuries referred to our regional trauma center were reviewed. Information had been recorded in the hospital's trauma registry and medical records were retrospectively reviewed for data pertaining to the injuries, with particular emphasis on neurological injuries and any associated details. RESULTS: A total of 107 patients were identified. Ninety percent of injured riders were male. The mean age was 34.4 years (range 10-70), with 7% younger than age 16. The mean Injury Severity Score was 12.0 ± 0.69 (range 1-34). Although not documented in all patients, alcohol use was found in 7.5% of the patients and drug use found in one patient. Documentation of helmet use was available for only 31 of the patients; of which 13% were not helmeted. Causes included being thrown, flipped, or roll-over (33%), striking a stationary object (27%), being struck by a snowmobile (9%), striking another snowmobile (5.5%) or a car, train, or truck (5.5%), being injured by the machine itself (9%), other (2%) or unspecified (18%). Head injuries occurred in 35% patients, including concussion, subarachnoid hemorrhage, subdural hematoma, contusion, and facial/skull fracture. Spinal fractures occurred in 21% of the patients. Fractures to the thoracic spine were the most common (50%), followed by the cervical (41%) and lumbar (36%) spine. There were also three brachial plexus injuries, one tibial nerve injury, and one internal carotid artery dissection. Average length of stay was 4.98 ± 0.56 days. Disposition was home (78%), home with services (12%), rehabilitation placement (9%), and one death. Details regarding other systemic injuries will also be reviewed. CONCLUSIONS: Snowmobiles are a significant source of multi-trauma, particularly neurological injury. Neurosurgeons can play key roles in advocating for neurological safety in snowmobiling.