Prediction of Admission Costs Following Anterior Cervical Discectomy and Fusion Utilizing Machine Learning.

STUDY DESIGN: Retrospective case series. OBJECTIVE: Predict cost following anterior cervical discectomy and fusion (ACDF) within the 90-day global period using machine learning models. BACKGROUND: The incidence of ACDF has been increasing with a disproportionate decrease in reimbursement. As bundled payment models become common, it is imperative to identify factors that impact the cost of care. MATERIALS AND METHODS: The Nationwide Readmissions Database (NRD) was accessed in 2018 for all primary ACDFs by the International Classification of Diseases 10th Revision (ICD-10) procedure codes. Costs were calculated by utilizing the total hospital charge and each hospital's cost-to-charge ratio. Hospital characteristics, such as volume of procedures performed and wage index, were also queried. Readmissions within 90 days were identified, and cost of readmissions was added to the total admission cost to represent the 90-day healthcare cost. Machine learning algorithms were used to predict patients with 90-day admission costs >1 SD from the mean. RESULTS: There were 42,485 procedures included in this investigation with an average age of 57.7±12.3 years with 50.6% males. The average cost of the operative admission was $24,874±25,610, the average cost of readmission was $25,371±11,476, and the average total cost was $26,977±28,947 including readmissions costs. There were 10,624 patients who were categorized as high cost. Wage index, hospital volume, age, and diagnosis-related group severity were most correlated with the total cost of care. Gradient boosting trees algorithm was most predictive of the total cost of care (area under the curve=0.86). CONCLUSIONS: Bundled payment models utilize wage index and diagnosis-related groups to determine reimbursement of ACDF. However, machine learning algorithms identified additional variables, such as hospital volume, readmission, and patient age, that are also important for determining the cost of care. Machine learning can improve cost-effectiveness and reduce the financial burden placed upon physicians and hospitals by implementing patient-specific reimbursement.

Allograft Versus Autograft in Anterior Cervical Discectomy and Fusion: A Propensity-Matched Analysis.

Objective To compare the 30-day complication rate associated with allograft versus autograft in anterior cervical discectomy and fusion (ACDF) and to determine preoperative factors that may influence complication rate. Methods The American College of Surgeons National Surgical Quality Improvement Program database was retrospectively queried from 2014 to 2017 for all procedures with CPT codes for ACDF (22551). Patients undergoing ACDF with either autograft or allograft were matched by propensity scores based on age, sex, body mass index, and comorbidities. The incidence of adverse events in the 30-day postoperative period was compared. Results A total of 21,588 patients met the inclusion and exclusion criteria. Following the 10:1 propensity match, 17,061 remained in the study (1,551 autograft and 15,510 allograft). The overall adverse event rate was 3.18%; 3.48% for autograft and 3.15% for allograft (P=0.494). Autograft had a significantly greater incidence of extended length of stay (>2 d) (LOS) (48.9% vs 34.8%; P<0.001). Multivariate analysis suggested that autograft selection was associated with extended LOS (OR 1.4; 95% CI 1.3-1.5). Conclusion The results of this study provide information regarding how graft selection can relate to extended hospital LOS and influence postoperative complications. Extended LOS may be associated with worse patient outcomes and increase the overall cost of care. Further study should be performed to determine which patients would benefit from autograft versus allograft with regards to long-term outcomes, in consideration of these increased short-term complications.

Surgical management of humeral shaft nonunions. Success of a consistent protocol over 17 years.

INTRODUCTION: Surgical treatment of humeral shaft nonunions is characterized by variability of fixation methods, graft choices, and rates of union and iatrogenic radial nerve palsy. The aim of the current study is to evaluate the union rate of humeral shaft aseptic nonunions and the rate of postoperative complications following a consistent management protocol. PATIENTS AND METHODS: This is a retrospective review of 41 consecutive adult patients (23 female and 18 male with a mean age of 42 years) with aseptic nonunions of the humeral shaft treated by the senior author in our institution over a 17-year period. Nonunions were located in the middle third of the diaphysis in 33 patients, in the distal third in 6, and in the proximal third in 2 patients. Comorbidities were present in 49% of patients and the most common were smoking in 27% and diabetes mellitus in 17% of patients. Patients were treated at an average of 24 months after their injury. Surgical protocol consisted of careful dissection of the radial nerve, debridement of the nonunion site, stable plate fixation and augmentation of local biology. RESULTS: Thirty-eight patients had mean clinical and radiographic follow-up of 9.4 months. All 38 nonunions healed at a mean time of 3.5 months. There were no persistent nonunions and no failures of fixation. None of the 40 patients with an intact radial nerve preoperatively developed any signs of radial nerve compromise after surgery. Complications consisted of one superficial infection (2%) that resolved with oral antibiotics and one deep infection (2%) that required implant removal and debridement. The mean pain score on the visual analog scale was 0.7. Mean elbow range of motion was 125 degrees with a mean extension deficit of 5 degrees and mean flexion of 130 degrees. CONCLUSIONS: Our surgical protocol achieved consistent healing of nonunions of the humeral shaft with a low complication rate and no iatrogenic radial nerve palsy, even in long-standing nonunions in patients with comorbidities.

Clinical and Radiographic Outcomes of Lateral Interbody Fusion for Adjacent Segment Degeneration.

STUDY DESIGN: Retrospective cohort study. OBJECTIVE: Assessment of outcomes in patients undergoing lateral interbody fusion as part of the surgical treatment of adjacent segment deterioration after previous lumbar spine fusion. METHODS: Adult patients with previous lumbar posterior spinal fusion who presented with adjacent segment degeneration and stenosis refractory to nonoperative treatment and who underwent lateral lumbar interbody fusion were retrospectively analyzed. Clinical and radiographic outcomes were assessed and comparisons made between preoperative baseline and postoperative values. RESULTS: Thirty-six patients with symptomatic adjacent segment degeneration at 46 motion segments were included. Thirty (83.3%) of the 36 patients had complete relief of both preoperative lower extremity pain and back pain at the time of final follow-up. Six (16.7%) of the 36 patients had persistent pain, though in all 6 cases, the pain was less postoperatively than preoperatively. Oswestry Disability Index scores were improved significantly at final follow-up (P = .001). Compared with preoperative baseline parameters, initial and final postoperative radiographs had an increase in segmental lordosis (P < .001 and P < .001, respectively), increase in overall lumbar lordosis (P < .05 and P = .094, respectively), decrease in segmental coronal angulation (P = .63 and P < .01, respectively), decrease in overall coronal angulation (P = .063 and P = .009, respectively), and increase in intervertebral height (P < .001 and P < .001, respectively). CONCLUSION: Lateral lumbar interbody fusion achieves favorable clinical and radiographic outcomes for the treatment of adjacent segment degeneration after previous lumbar fusion. LEVEL OF EVIDENCE: 4.

Periosteal turndown flap for posterior occipitocervical fusion: a technique review.

PURPOSE: Recently, several authors have proposed techniques for improving the fusion rate in pediatric posterior occipitocervical fusion including a variety of implants and the use of bone morphogenetic protein. A technique by Koop et al. using a periosteal flap for occipitocervical arthrodesis was described in 1984. METHODS: A straight incision is made about the posterior neck to expose the occipitocervical region from the inion superiorly to the lowest cervical vertebrae to be fused inferiorly. The occiput is exposed superficial to the periosteum, which is then reflected and elevated from the occiput. The attachment is preserved at the caudal base of the flap and reflected over the intended area of fusion. When possible, fixation is then performed with cables, wires, screws, hooks, or plates. CASE EXAMPLE: A 6-year-old male with an occiput to C2 distraction injury underwent posterior spinal fusion from occiput to C3 using sublaminar wires, periosteal turndown flap, and autologous iliac crest bone graft. CONCLUSION: In small children with traumatic upper cervical spine instability, the periosteal turndown technique may be used as a safe adjunct for occipitocervical fusions.

Walking activity during daily living in children with myelomeningocele.

PURPOSE: To quantify the walking activity of children with myelomeningocele during daily living. METHOD: Walking activity was measured using a StepWatch activity monitor over one week in 47 children with myelomeningocele (27 males; 9 years 11 months SD 2 years 7 months; 18 sacral, 9 low lumbar, 20 mid-high lumbar) and seven children with typical development (5 males; 11 years 1 month SD 1 year 11 months) in a prospective, cross-sectional study. Average total steps per day, number of steps and minutes spent at low, medium and high intensity stepping were evaluated. Groups were compared using t-tests and chi-squared tests with Bonferroni post-hoc adjustment. RESULTS: Children with sacral and low lumbar myelomeningocele exhibited no significant differences in demographic characteristics or walking performance compared to typically developing children. Children with mid-high lumbar myelomeningocele exhibited higher BMI percentile than the control group (p = 0.04) and took fewer total steps per day than all other groups (p ≤ 0.04). Children with mid-high lumbar myelomeningocele also spent significantly less time taking steps at all intensity levels, particularly medium-intensity, than the sacral and low lumbar groups (p ≤ 0.04). CONCLUSIONS: Children with sacral and low lumbar myelomeningocele had walking performance similar to typically developing children despite a common need for braces and assistive devices. Children with mid-high lumbar myelomeningocele were less active, which may lead to heightened risk for secondary health conditions in addition to those associated with myelomeningocele. Implications for Rehabilitation Obesity, muscle weakening and disuse osteoporosis are issues for those with myelomeningocele, all of which are affected by walking activity. Understanding walking activity and intensity in children and adolescents with myelomeningocele may aid in developing focused rehabilitation interventions and strategies. Real world walking activity as an objective and quantified measure has the potential to help guide therapists and surgeons to more effective treatments.

Repeat hamstring lengthening for crouch gait in children with cerebral palsy.

BACKGROUND: Progressive crouch gait occurs in patients with cerebral palsy with increasing age. Hamstring lengthening improves crouch in these patients, but hamstring contractures can recur over time. The purpose of this study was to determine whether revision hamstring lengthening is as effective as primary lengthening in improving crouched gait. METHODS: Retrospective review was performed for 39 patients with static encephalopathy, average age 10±4 years, who underwent hamstring lengthening. Twenty-one subjects underwent a single hamstring lengthening (HSL group), and 18 underwent repeat HSL (rHSL group). Range of motion (ROM) and kinematic measures from preoperative and postoperative gait analysis testing were compared within and between groups using t tests, χ2 tests, and multiple regression analyses as appropriate. RESULTS: A total of 15/21 subjects in the HSL group (71%) improved stance knee extension by ≥10 degrees, as compared with 5/18 (28%) in the rHSL group (P=0.007). The HSL group had improved popliteal angle, static knee and hip extension ROM, and knee flexion at initial contact and in stance phase (P<0.003). No such improvements were seen in the rHSL group. Popliteal angle, knee and hip extension ROM, and knee flexion at initial contact and in stance phase had significantly greater improvement in the HSL than the rHSL group (P<0.01). These differences persisted after adjusting for preoperative minimum hip flexion in stance, the only variable that differed between groups preoperatively. CONCLUSIONS: Repeat hamstring lengthening may delay progressive crouch, but does not result in long-term correction of crouch gait. Recurrent crouch may be caused by other factors such as quadriceps insufficiency, and may reflect the natural history of CP. Patients with recurrent crouch after hamstring lengthening are likely to benefit more from alternative surgical interventions to improve their knee position and function during gait. LEVEL OF EVIDENCE: Level IV-case series.