Faculty Bibliography

STUDY DESIGN/UNASSIGNED:Retrospective cohort study. OBJECTIVE/UNASSIGNED:The aim of this study is to determine if there is a correlation between the amount of facet distraction and postoperative patient-reported outcomes after ACDF. METHODS/UNASSIGNED:A retrospective cohort analysis of patients undergoing 1 to 3 level ACDF for degenerative pathologies at a single academic center was performed. Each patient received upright, lateral cervical spine x-rays at the immediate postoperative time point from which interfacet distance (facet distraction) was measured. Patient-reported outcome measures including NDI, PCS-12, MCS-12, VAS Neck, and VAS Arm pain scores were obtained preoperatively and at short-term (<3 months) and long-term (>1 year) follow-up. Receiver operating curves were generated to evaluate the possibility of a critical interfacet distraction distance. Univariate and multivariate analysis were performed to compare outcomes between groups based on the degree of facet distraction. RESULTS/UNASSIGNED:A total of 229 patients met the inclusion criteria. Receiver operating curves failed to yield a critical interfacet distraction distance associated with worse post-operative outcomes. Patients were instead grouped based on facet distraction distance below and above the third quartile (0.8mm-2.0 mm, 2.0mm-3.7 mm), with 173 and 56 patients in each respective group. Univariate analysis did not detect any statistically significant differences in outcome measures, recovery ratio, or % MCID achievement at short- and long-term follow-up between groups. Multivariate analysis also failed to demonstrate any significant differences between the facet distraction groups. CONCLUSION/UNASSIGNED:Increased interfacet distance did not correlate with increased neck pain or disability after an ACDF.

BACKGROUND CONTEXT:The majority of patients with preoperative upper extremity weakness show improvements in motor function after anterior cervical discectomy and fusion (ACDF). Although numerous studies have examined both the extent and time course to which motor function can be expected to improve, few have shown that these improvements in motor function translate to improved health related quality of life (HRQOL) outcomes. PURPOSE:The purpose of this study was to examine the effect of preoperative weakness and duration of symptoms on HRQOL outcomes in patients who underwent ACDF. STUDY DESIGN:Retrospective cohort study. PATIENT SAMPLE:Adult patients who underwent an ACDF procedure at an academic hospital from January 2015 to December 2016 by a fellowship-trained spine surgeon. OUTCOME MEASURES:The primary outcomes of interest were HRQOL outcomes: Short Form-12 Physical/Mental Component Scores (SF-12 PCS/MCS), Neck Disability Index (NDI), and Visual Analog Scale Arm/Neck scores (VAS Arm/Neck). METHODS:Patient demographics, surgical case characteristics, and motor strength exams were collected in patients who underwent ACDF over a 2-year period. Preoperative weakness was defined by a strength grade ≤3 (on a scale from 0 to 5) in at least one upper extremity muscle group. Multivariate linear regression analysis was performed to determine the effect of the preoperative weakness on HRQOL outcomes. RESULTS:Of the 276 patients identified, 45 (16.3%) showed evidence of preoperative weakness, 44 (97.8%) of which showed subsequent postoperative motor improvements after ACDF. All patients reported significant improvements in all HRQOL outcome measures. Patients with preoperative weakness reported significantly worse preoperative VAS Arm (6.9 vs. 5.2; p=.01) and VAS Neck (6.1 vs. 4.8; p=.02) pain scores. Compared with patients without preoperative weakness, those with preoperative weakness reported significantly more improvement in NDI (β: -10.9; p=.001). Patients with symptoms greater than or equal to 12 months and preoperative weakness showed significantly less improvement in NDI (β: 14.8; p=.03). CONCLUSIONS:Patients with preoperative weakness generally exhibited worse pain and HRQOL measures preoperatively, and showed greater potential for improvement after ACDF. Patients with a shorter duration of preoperative weakness had greater potential for improvement in HRQOL measures after ACDF compared with those with longer duration of symptoms. ACDF is an effective procedure to improve strength and HRQOL measures across all patient groups under appropriate indications.

STUDY DESIGN/METHODS:Histological features of the intervertebral disc (IVD)-endplate interface were analyzed. OBJECTIVE:To define cartilaginous and bony vertebral endplate in commonly used laboratory animals and compare with that of the humans. SUMMARY OF BACKGROUND DATA/BACKGROUND:Endplates are crucial for the IVD nutrient supply: the IVDs have limited blood supply; most nutrients diffuse through endplates to nourish the discs. Various animal models of IVD and endplate degeneration have been used to study the etiology and treatments of spinal disorders. However, because humans are biped, the spine mechanics differ significantly from other mammals. Translation of animal research findings requires a characterization and comparison of the vertebral endplate in the respective species. In this study, we compared the endplate structure of laboratory animal species at the age range commonly used for modeling spine degeneration with that of an adult human. METHODS:Mouse, rat, rabbit, goat, and human IVDs and the adjacent vertebral bodies were isolated from the lower lumbar spine. Tissues were stained with Alcian Blue, counterstained with hematoxylin and eosin. RESULTS:Structure of the vertebral endplate varied significantly between the adult animal species and that of the humans. Growth plates persisted in all adult animals studied, whereas the growth plate is absent in the adult humans. In the mice and rats, the cartilaginous endplates are in continuation with the growth plates, with only a small bony center. Rabbits and goats have a bony layer between cartilaginous endplate and the growth plate. The human endplate consist of a cartilaginous layer and the bony endplate. CONCLUSION/CONCLUSIONS:Significant differences exist in histological features of the endplate across animal species and that of the humans. Consideration should be given when animal models are used to study IVD degeneration and surgical treatments. LEVEL OF EVIDENCE/METHODS:5.

The natural history of early onset scoliosis is dismal and associated with poor pulmonary function and increased mortality. Although limited in situ fusion may be appropriate for certain types of congenital scoliosis deformities, spinal deformity that affects young children often requires a "growth friendly" surgical approach that allows for curve control while maintaining growth of the spine and thorax. Growth-friendly surgical management of early onset scoliosis can follow a distraction-based (ie, growth rods, vertical expandable prosthetic titanium rib [Synthes, West Chester, PA]), guided-growth (ie, Luque trolley technique, Shilla technique), or compression-based (ie, tethers, staples) strategy.

Recurrent lumbar disk herniation is the most common complication following primary open diskectomy. It is defined as recurrent back and/or leg pain after a definite pain-free period lasting at least 6 months from initial surgery. Careful neurologic examination is critical, and laboratory tests should be ordered to evaluate for infection. Imaging demonstrates disk herniation at the previously operated level. It is important to differentiate recurrent disk herniation from postoperative epidural scar because the latter may not benefit from reoperation. Treatment of recurrent lumbar disk herniation includes aggressive medical management and surgical intervention. Surgical techniques include conventional open diskectomy, minimally invasive open diskectomy, and open diskectomy with fusion. Fusion is necessary in the presence of concomitant segmental instability or significant foraminal stenosis resulting from disk space collapse.

Central cord syndrome is the most common type of incomplete spinal cord injury. This syndrome most often occurs in older persons with underlying cervical spondylosis caused by a hyperextension mechanism. It also occurs in younger persons who sustain trauma to the cervical spine and, less commonly, as a result of nontraumatic causes. The upper extremities are more affected than the lower extremities, with motor function more severely impaired than sensory function. Central cord syndrome presents a spectrum, from weakness limited to the hands and forearms with sensory preservation, to compete quadriparesis with sacral sparing as the only evidence of incomplete spinal cord injury. Historically, treatment has been nonsurgical, but recovery is often incomplete. Early surgical treatment of central cord syndrome remains controversial. However, recent studies have shown benefits, particularly of early surgery to decompress the spinal cord in patients with pathologic conditions revealed by radiography or MRI.