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Gautam Nayar, Daniel J. Blizzard, Timothy Y. Wang, Steven Cook, Adam G. Back, David Vincent, and Isaac O. Karikari

OBJECTIVE

A previous study found that ultra-low radiation imaging (ULRI) with image enhancement significantly decreases radiation exposure by roughly 75% for both the patient and operating room personnel during minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF) (p < 0.001). However, no clinical data exist on whether this imaging modality negatively impacts patient outcomes. Thus, the goal of this randomized controlled trial was to assess pedicle screw placement accuracy with ULRI with image enhancement compared with conventional, standard-dose fluoroscopy for patients undergoing single-level MIS-TLIF.

METHODS

An institutional review board–approved, prospective internally randomized controlled trial was performed to compare breach rates for pedicle screw placement performed using ULRI with image enhancement versus conventional fluoroscopy. For cannulation and pedicle screw placement, surgery on 1 side (left vs right) was randomly assigned to be performed under ULRI. Screws on the opposite side were placed under conventional fluoroscopy, thereby allowing each patient to serve as his/her own control. In addition to standard intraoperative images to check screw placement, each patient underwent postoperative CT. Three experienced neurosurgeons independently analyzed the images and were blinded as to which imaging modality was used to assist with each screw placement. Screw placement was analyzed for pedicle breach (lateral vs medial and Grade 0 [< 2.0 mm], Grade 1 [2.0–4.0 mm], or Grade 2 [> 4.0 mm]), appropriate screw depth (50%–75% of the vertebral body’s anteroposterior dimension), and appropriate screw angle (within 10° of the pedicle angle). The effective breach rate was calculated as the percentage of screws evaluated as breached > 2.0 mm medially or postoperatively symptomatic.

RESULTS

Twenty-three consecutive patients underwent single-level MIS-TLIF, and their sides were randomly assigned to receive ULRI. No patient had immediate postoperative complications (e.g., neurological decline, need for hardware repositioning). On CT confirmation, 4 screws that had K-wire placement and cannulation under ULRI and screw placement under conventional fluoroscopy showed deviations. There were 2 breaches that deviated medially but both were Grade 0 (< 2.0 mm). Similarly, 2 breaches occurred that were Grade 1 (> 2.0 mm) but both deviated laterally. Therefore, the effective breach rate (breach > 2.0 mm deviated medially) was unchanged in both imaging groups (0% using either ULRI or conventional fluoroscopy; p = 1.00).

CONCLUSIONS

ULRI with image enhancement does not compromise accuracy during pedicle screw placement compared with conventional fluoroscopy while it significantly decreases radiation exposure to both the patient and operating room personnel.

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Timothy Y. Wang, Vikram A. Mehta, Eric W. Sankey, Khoi D. Than, C. Rory Goodwin, Isaac O. Karikari, Robert E. Isaacs, and Muhammad M. Abd-El-Barr

OBJECTIVE

The rate of symptomatic adjacent-segment disease (ASD) after newer minimally invasive techniques, such as lateral lumbar interbody fusion (LLIF), is not known. This study aimed to assess the incidence of surgically significant ASD in adult patients who have undergone index LLIF and to identify any predictive factors.

METHODS

Patients who underwent index LLIF with or without additional posterior pedicle screw fixation between 2010 and 2012 and received a minimum of 2 years of postoperative follow-up were retrospectively included. Demographic and perioperative data were recorded, as well as radiographic data and immediate perioperative complications. The primary endpoint was revision surgery at the level above or below the previous construct, from which a survivorship model of patients with surgically significant symptomatic ASD was created.

RESULTS

Sixty-seven patients with a total of 163 interbody levels were included in this analysis. In total, 17 (25.4%) patients developed surgically significant ASD and required additional surgery, with a mean ± SD time to revision of 3.59 ± 2.55 years. The mean annual rate of surgically significant ASD was 3.49% over 7.27 years, which was the average follow-up. One-third of patients developed significant disease within 2 years of index surgery, and 1 patient required surgery at the adjacent level within 1 year. Constructs spanning 3 or fewer interbody levels were significantly associated with increased risk of surgically significant ASD; however, instrument termination at the thoracolumbar junction did not increase this risk. Surgically significant ASD was not impacted by preoperative disc height, foraminal area at the adjacent levels, or changes in global or segmental lumbar lordosis.

CONCLUSIONS

The risk of surgically significant ASD after LLIF was similar to the previously reported rates of other minimally invasive spine procedures. Patients with shorter constructs had higher rates of subsequent ASD.

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Eric W. Sankey, Vikram A. Mehta, Timothy Y. Wang, Tracey T. Than, C. Rory Goodwin, Isaac O. Karikari, Christopher I. Shaffrey, Muhammad M. Abd-El-Barr, and Khoi D. Than

Spine surgery has been disproportionately impacted by medical liability and malpractice litigation, with the majority of claims and payouts related to procedural error. One common area for the potential avoidance of malpractice claims and subsequent payouts involves misplaced pedicle and/or lateral mass instrumentation. However, the medicolegal impact of misplaced screws on spine surgery has not been directly reported in the literature. The authors of the current study aimed to describe this impact in the United States, as well as to suggest a potential method for mitigating the problem.

This retrospective analysis of 68 closed medicolegal cases related to misplaced screws in spine surgery showed that neurosurgeons and orthopedic spine surgeons were equally named as the defendant (n = 32 and 31, respectively), and cases were most commonly due to misplaced lumbar pedicle screws (n = 41, 60.3%). Litigation resulted in average payouts of $1,204,422 ± $753,832 between 1995 and 2019, when adjusted for inflation. The median time to case closure was 56.3 (35.2–67.2) months when ruled in favor of the plaintiff (i.e., patient) compared to 61.5 (51.4–77.2) months for defendant (surgeon) verdicts (p = 0.117).

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Stephen M. Bergin, Timothy Y. Wang, Christine Park, Shashank Rajkumar, C. Rory Goodwin, Isaac O. Karikari, Muhammad M. Abd-El-Barr, Christopher I. Shaffrey, Chester K. Yarbrough, and Khoi D. Than

OBJECTIVE

The use of osteobiologics, engineered materials designed to promote bone healing by enhancing bone growth, is becoming increasingly common for spinal fusion procedures, but the efficacy of some of these products is unclear. The authors performed a retrospective, multi-institutional study to investigate the clinical and radiographic characteristics of patients undergoing single-level anterior cervical discectomy with fusion performed using the osteobiologic agent Osteocel, an allograft mesenchymal stem cell matrix.

METHODS

The medical records across 3 medical centers and 12 spine surgeons were retrospectively queried for patients undergoing single-level anterior cervical discectomy and fusion (ACDF) with the use of Osteocel. Pseudarthrosis was determined based on CT or radiographic imaging of the cervical spine. Patients were determined to have radiographic pseudarthrosis if they met any of the following criteria: 1) lack of bridging bone on CT obtained > 300 days postoperatively, 2) evidence of instrumentation failure, or 3) motion across the index level as seen on flexion-extension cervical spine radiographs. Univariate and multivariate analyses were then performed to identify independent preoperative or perioperative predictors of pseudarthrosis in this population.

RESULTS

A total of 326 patients met the inclusion criteria; 43 (13.2%) patients met criteria for pseudarthrosis, of whom 15 (34.9%) underwent revision surgery. There were no significant differences between patients with and those without pseudarthrosis, respectively, for patient age (54.1 vs 53.8 years), sex (34.9% vs 47.4% male), race, prior cervical spine surgery (37.2% vs 33.6%), tobacco abuse (16.3% vs 14.5%), chronic kidney disease (2.3% vs 2.8%), and diabetes (18.6% vs 14.5%) (p > 0.05). Presence of osteopenia or osteoporosis (16.3% vs 3.5%) was associated with pseudarthrosis (p < 0.001). Implant type was also significantly associated with pseudarthrosis, with a 16.4% rate of pseudarthrosis for patients with polyetherethereketone (PEEK) implants versus 8.4% for patients with allograft implants (p = 0.04). Average lengths of follow-up were 27.6 and 23.8 months for patients with and those without pseudarthrosis, respectively. Multivariate analysis demonstrated osteopenia or osteoporosis (OR 4.97, 95% CI 1.51–16.4, p < 0.01) and usage of PEEK implant (OR 2.24, 95% CI 1.04–4.83, p = 0.04) as independent predictors of pseudarthrosis.

CONCLUSIONS

In patients who underwent single-level ACDF, rates of pseudarthrosis associated with the use of the osteobiologic agent Osteocel are higher than the literature-reported rates associated with the use of alternative osteobiologics. This is especially true when Osteocel is combined with a PEEK implant.

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Rafael De la Garza Ramos, Christine Park, Edwin McCray, Meghan Price, Timothy Y. Wang, Tara Dalton, César Baëta, Melissa M. Erickson, Norah Foster, Zach Pennington, John H. Shin, Daniel M. Sciubba, Khoi D. Than, Isaac O. Karikari, Christopher I. Shaffrey, Muhammad M. Abd-El-Barr, Reza Yassari, and C. Rory Goodwin

OBJECTIVE

In patients with metastatic spinal disease (MSD), interhospital transfer can potentially impact clinical outcomes as the possible benefits of transferring a patient to a higher level of care must be weighed against the negative effects associated with potential delays in treatment. While the association of clinical outcomes and transfer status has been examined in other specialties, the relationship between transfer status, complications, and risk of mortality in patients with MSD has yet to be explored. The purpose of this study was to examine the impact of transfer status on in-hospital mortality and clinical outcomes in patients diagnosed with MSD.

METHODS

The National (Nationwide) Inpatient Sample (NIS) database was retrospectively queried for adult patients diagnosed with vertebral pathological fracture and/or spinal cord compression in the setting of metastatic disease between 2012 and 2014. Demographics, baseline characteristics (e.g., metastatic spinal cord compression [MSCC] and paralysis), comorbidities, type of intervention, and relevant patient outcomes were controlled in a multivariable logistic regression model to analyze the association of transfer status with patient outcomes.

RESULTS

Within the 10,360 patients meeting the inclusion and exclusion criteria, higher rates of MSCC (50.2% vs 35.9%, p < 0.001) and paralysis (17.3% vs 8.4%, p < 0.001) were observed in patients transferred between hospitals compared to those directly admitted. In univariable analysis, a higher percentage of transferred patients underwent surgical intervention (p < 0.001) when compared with directly admitted patients. After controlling for significant covariates and surgical intervention, transferred patients were more likely to develop in-hospital complications (OR 1.34, 95% CI 1.18–1.52, p < 0.001), experience prolonged length of stay (OR 1.33, 95% CI 1.16–1.52, p < 0.001), and have a discharge disposition other than home (OR 1.70, 95% CI 1.46–1.98, p < 0.001), with no significant difference in inpatient mortality rates.

CONCLUSIONS

Patients with MSD who were transferred between hospitals demonstrated more severe clinical presentations and higher rates of inpatient complications compared to directly admitted patients, despite demonstrating no difference in in-hospital mortality rates.