Faculty Bibliography

STUDY DESIGN: A retrospective review of 74 consecutive, surgical patients with neuromuscular scoliosis (NMS). OBJECTIVE: This study evaluates the distribution of hospital and operating room costs incurred during surgical correction of NMS. BACKGROUND DATA: Recent studies have demonstrated that surgical treatment improves both medical outcomes and the quality of life in patients with progressive NMS. Characterization of the costs incurred at the time of surgery and hospitalization will facilitate the identification of opportunities for cost reduction. METHODS: Demographic data collected included gender, age, preoperative height, weight, and BMI. Major coronal curvatures and T5-T12 kyphosis were assessed from radiographs. Construct type and number of screws, hooks, and wires implanted were recorded. Surgical costs were calculated based on cost of surgical correction, hospital stay, and postoperative care. RESULTS: Mean age was 15.8 +/- 7.3 years; 57% were male. Comorbidities included cerebral palsy (28%) and familial dysautonomia (14%). The mean preoperative major curve magnitude was 60 degrees ; minor curve magnitude was 33 degrees . Posterior approach (76%) and pedicle screws (75%) were predominantly utilized. The average length of hospitalization was 8 days (range: 3 to 47). There were six major complications (8%). The total surgical cost was $50,096 +/- $23,998. The highest individual cost was for implants ($13,916; 24% of total costs). The second highest was inpatient room and ICU costs ($12,483; 22%); bone grafts were the third ($6,398; 11%). Increased major and minor structural curve, increased total (A/P) levels fused, and increased length of hospital stay predicted an increase in total cost. CONCLUSIONS: Major contributors to cost in NMS surgery are implants, inpatient room and ICU costs, and bone grafts. Independent predictors of higher cost are the degree of major and minor structural curve, total number of A/P levels fused, and length of hospital stay. These conclusions provide insight into costs associated with care for a medically fragile and challenging patient population.

BACKGROUND CONTEXT: The use of postoperative drains has been evaluated extensively in the joint arthroplasty literature, but to a much lesser extent in the spine literature. The prevailing consensus in the realm of arthroplasty is that drains do not show a benefit in terms of reducing infections and other complications, and may actually increase transfusion rates. PURPOSE: The purpose of this study is to determine if the placement of a drain and the duration of time the drain is in place increase the likelihood of surgical site infections occurring in spinal patients. STUDY DESIGN/SETTING: This is a single-institution, retrospective review of data collected as part of a previous randomized, controlled trial. PATIENT SAMPLE: Eligible patients include those that were enrolled in a previous randomized, controlled trial that compared two prophylactic antibiotic treatments with the placement of a postoperative spinal drain. Data from patients consented for the same study that did not receive drains is also included. OUTCOME MEASURES: Outcome measures include the incidence of postoperative surgical site infections and statistically identified risk factors. METHODS: The medical records of patients that did and did not receive spinal drains were retrospectively reviewed. Demographic, operative and perioperative measures were statistically evaluated to compare patients that did and did not receive drains. Patients with drains were classified by the duration of the drain (fewer or greater than 3 days) as well as by the length of their postoperative antibiotic treatment - patients that received postoperative antibiotics for only 24 hours were part of the TF group, while patients that received antibiotics for the duration of the drain were part of the DUR group. Patients without drains were considered to be in the ND group. Risk factors for infection, including diabetes, smoking, drugs, alcohol, prior surgery, operating surgeon, and surgical approach were also evaluated. RESULTS: ND patients had lower mean age (p<0.01), ASA score (p<0.02), operative time (p<0.01), estimated blood loss (p<0.01), transfusion rate (p<0.01), and length of stay (p<0.01) than patients that received drains. ND patients (n5129) had a mean infection rate of 7.0%; this was not significantly different from TF patients (12.1%, n5199, p>0.14). However, the infection rate in ND patients was significantly different than the infection rate amongst DUR patients (14.4%, n5167, p>0.05). TF patients whose drains were in place for fewer than 3 days (n5156) had a significantly lower rate of infection (8.3%) than those whose drains were in place for longer than 3 days (23.8%) (n542) (p>0.03). There were significant differences in infection rates between ND patients and those who had drains for more than 3 days, regardless of antibiotic treatment (TF, p>0.02; DUR, p>0.03). Risk factors amongst TF patients were age (p>0.01), diabetes (0.04), BMI (p>0.03), length of stay (p<0.01), and drain duration (p>0.03). For DUR patients, risk factors for infection were age (p>0.05), smoking (p>0.01) and length of stay (p<0.01). The only identified risk factor in ND was the surgical approach (p<0.01). CONCLUSIONS: The findings of this study suggest that when compared to patients that do not receive postoperative spinal drains, patients with drains are more likely to develop a surgical site infection if their antibiotics are continued for the duration of time the drain is in place, rather than for 24 hours only. Our results also suggest that, regardless of antibiotic treatment, patients whose spinal drains remain in place for longer than 3 days have a higher rate of developing postoperative surgical site infections than both those who do not receive drains and those whose drains are in place for less than 3 days. Therefore, that there may be a need for greater prophylactic measures in spinal patients that have postoperative drains for more than 3 days

Introduction While lumbar spinal fusion is commnly performed for back and leg pain arising from spinal stenosis with or without spondylolisthesis, there exists significant potential for perioperative morbidity and clinically relevant adjacent segment disease. Direct decompression and interlaminar stabilization with coflexdegree has recently demonstrated equivalent or superior outcomes compared with posterolateral fusion (PLF) in patients with stenosis with up to Grade 1 spondylolisthesis. It remains unclear, however, whether or not interlaminar stabilization can sufficiently stabilize low-grade spondylolisthesis and lead to outcomes comparable to that seen withPLF. Methods Prospective, randomized, multicenter FDA IDE trial comparing coflexdegree interlaminar stabilization (n = 140) with laminectomy and PSF (n = 72) to treat 1- and 2- level spinal stenosis up to Grade I degenerative spondylolisthesis. In the spondylolisthesis-only subset (current study) there were 64 coflexdegree and 34 PSF patients with complete data at 2 years. Results Coflexdegree patients experienced significantly shorter operative times (p<0.001), EBL (p<0.001), and length of stay (p<0.001). ODI scores were lower at all post-operative timepoints with coflexdegree, with significant improvement at 3 months (p = 0.034) and a trend at 6 months (p = 0.093). The proportion of coflexdegree patients achieving a 15-point ODI reduction at 24 months was 88.0 % (44/50) compared with 76.7 % with PSF (23/30). ZCQ outcomes were significantly improved with coflexdegree at 2 years in Symptom Severity (p = 0.041), Physical Function (p = 0.048), and Satisfaction (p = 0.015). VAS Back and Leg scores revealed equivalent improvement with either coflexdegree or PSF. Based on the stringent FDA composite for overall success including ODI improvement C15 points, no device-related complications, no reoperations, and no epidural injections, 67.2 % (41/61) of coflexdegree and 63.6 % (21/33) of PSF with spondylolisthesis succeeded, respectively. Finally, PSF exhibited significantly greater angulation (3.77 vs. 6.38degree, p = 0.0003) and translation (0.78 vs. 1.15 mm, p = 0.049) at the cranial adjacent level at 2 years. Conclusions Low-grade spondylolisthesis can be effectively treated by decompression and coflexdegree interlaminar stabilization with equivalent or superior results at 2 years when compared with laminectomy and PSF. The reduced perioperative morbidity, shorter hospital length of stay, equivalent or superior clinical outcomes, and significantly reduced adjacent segment stresses supports the use of coflexdegree as a viable alternative to PSF in low-grade spondylolisthesis

STUDY DESIGN.: In vitro cadaveric study. OBJECTIVE.: The purpose of this study was to quantify the relative biomechanical protection resulting from "saving a level" in long spinal fusions. SUMMARY OF BACKGROUND DATA.: "Saving levels" in spinal deformity surgery is desirable. Constructs with lowest instrumented vertebra (LIV) in the lumbar spine may increase loads on unfused lumbar intervertebral discs, leading to accelerated disc degeneration. No study to date has quantified the relative pressure changes that occur in the unfused caudal discs with progressively longer fusions. METHODS.: We used a validated in vitro cadaveric long fusion model to assess intradiscal pressures (IDPs) below simulated fusions. Eight fresh frozen T8-S1 specimens were instrumented from T8 to L5. A follower-type loading system and 7.5-N.m moments were applied in flexion and extension. IDP profiles were assessed with a pressure transducer. After acquiring IDP measurements at a given construct length, the rod was cut 1 level higher until LIV = T12. IDP data from each unfused disc were averaged and normalized to the mean value of the disc when immediately subjacent to the LIV. RESULTS.: In both flexion and extension, the mean normalized IDP of the unfused discs below the LIV increased with increasing fusion length. For each 1-level increase in construct length, pressure increased by 3.2% +/- 4.8% in flexion and 4.3% +/- 4.5% in extension for each unfused disc. Although the differences in pressure for a given unfused disc with differing LIV were not significant, there were significant differences between unfused discs at a given LIV. With shorter fusion lengths, pressure in the disc immediately subjacent to the fusion was consistently greater than for the caudal-most discs. CONCLUSION.: Unfused caudal lumbar discs experienced increased IDPs with increasing length of instrumentation, most notably at the subjacent discs closest to the LIV.

Spine Tango is currently the only international spine registry in existence. It was developed under the auspices of Eurospine, the Spine Society of Europe, and is hosted at the University of Bern, Switzerland. The HJD Spine Center successfully tested Spine Tango during a 3-month pilot study and has since expanded documentation activities to more surgeons. Workflow integration and dedicated research staff are key factors for such an endeavor. Participation enables benchmarking against national and international peers and outcome research and quality assurance of surgical and non-surgical treatments.

Introduction: The gold standard treatment for low-grade degenerative spondylolisthesis and spinal stenosis remains laminectomy and posterior spinal fusion (PSF) with pedicle screw implants. The potential for substantial perioperative morbidity and adjacent segment degeneration has led to the search for motion-preserving alternatives that still allow for direct neurologic decompression and stabilization. This is a prospective, randomized, multicenter FDA IDE trial comparing coflex interlaminar stabilization (n=140) with decompression and PSF (n=72) for the treatment of the following conditions: 1) low-grade spondylolisthesis (up to Grade I), and 2) spinal stenosis (1- and 2-level) with disabling low back pain. In the current study, we report exclusively on the subset of patients at 2 years from this IDE trial with low-grade spondylolisthesis. Methods: In the spondylolisthesis subset there were 64 coflex and 34 PSF patients with complete data at 2 years. Study inclusion consisted of moderate to severe spinal stenosis with significant low back pain (VAS Back Pain >50/100) and significant disability (ODI >40%), with Grade I spondylolisthesis, at spinal segments from L1-L5. Results: Follow-up for the entire evaluable cohort at 24 months was 96.6% and 98.6% for coflex and PSF control groups, respectively. There were no group differences at baseline in any demographic or clinical parameters in the spondylolisthesis cohort. Coflex patients experienced significantly shorter operative times (p<0.001), EBL (p<0.001), and length of stay (p<0.001) by an average of 1.2 days compared with PSF. ODI scores were lower at all post-operative time points in the coflex cohort, with significant improvement at 3 months (p=0.034) and a trend at 6 months (p=0.093). Despite equivalence at baseline, 2 year coflex ODI scores averaged 19.6 compared with 26.0 for PSF (p=0.141). The proportion of coflex patients achieving a 15 point ODI reduction at 24 months was 88.0% (44/50) compared with 76.7% with PSF (23/30). ZCQ outcome!

STUDY DESIGN: Biomechanical study. OBJECTIVE: To evaluate the cervical facet loading profile of an intervertebral cervical disc prosthesis incorporating a unique saddle-shaped articulation and to determine the effect of implantation of the prosthesis on both the loading curve and area distribution of facet loading, when compared with that of an intact specimen. SUMMARY OF BACKGROUND DATA: This is the first study that examines the effect of implantation of a cervical disc replacement on the loading of the facet joints. METHODS: Fresh-frozen ovine cervical spine specimens were used. Specimens were prepared and disarticulated to yield 6 functional spinal units, which were secured and mounted in a custom fixture on a material testing apparatus. A novel pressure sensor was constructed by combining a resistive ink thin film sensor with Fuji pressure-sensitive film. The sensor was calibrated before unilateral insertion into the cervical facet joint via a small arthrotomy. Specimens were tested in both intact condition and after surgical intervention consisting of discectomy and implantation of an intervertebral cervical disc prosthesis (CerviCore, Stryker Spine, Allendale, NJ). Specimens were tested in flexion, extension, and lateral bending to 3 Nm and in torsion to 2.5 Nm. At the termination of each loading profile, the load was maintained for 30 seconds to permit full exposure of the Fuji film. For each configuration, the maximum resultant load, load rate, and contact area pressure at the endpoint of the loading profile were determined. A paired Student t test was used to determine the differences between the intact specimen and the specimen with an implanted intervertebral disc prosthesis. RESULTS: There were no statistically significant differences in mean or maximum pressures between the intact specimen and the specimen with an intervertebral disc in all loading configurations. Similarly, there was no significant difference in the total measured force between the groups in all loading configurations. There was no significant difference in contact areas between the groups in flexion, lateral bending, and torsion. When evaluated in extension, the intact specimen had a mean contact area of 0.8 cm compared with 0.5 cm for the intervertebral disc (P<0.02). CONCLUSIONS: Biomechanical testing in an ovine model demonstrated no significant difference in measured facet pressures and forces between an intact native cervical disc specimen and a cervical intervertebral disc prosthesis using a saddle-shaped articulation. Peak and mean pressures were not demonstrated to be significantly different between the implanted and intact disc conditions. Implantation of the prosthesis resulted in a significant reduction of contact area under extension moments

BACKGROUND CONTEXT: Advances in technology are influencing the way that medical information is archived and shared. Considering that an estimated two-thirds of the world has little or no orthopedic care, high demand exists for adequate consultation regarding diagnostic images in orthopedic specialties. PURPOSE: To validate the use of photographed scoliosis films for the accurate interpretation of Cobb angles. STUDY DESIGN: Retrospective review. PATIENT SAMPLE: Thirty scoliosis radiographs. OUTCOME MEASURE: Cobb angle. METHODS: Thirty scoliosis radiographs were photographed using a digital camera from a straight and a 45 degrees angle position. Cobb angles were then measured on the digital images using standard measurement software. Comparison was made between two types of curves: convex and concave, relative to the left side (side for the angled position). RESULTS: There was excellent reproducibility between the measurements of the conventional radiographs and the photographs taken from a straight on position, p value of .97 for convex curves and p value of .98 for concave curves. Photographs taken from a 45 degrees angle significantly increased the magnitude of the curve convex to the angle (p=.001). CONCLUSION: Sharing photographs of scoliosis radiographs can be done with reliability if the image is taken directly in front of the viewbox rather than at an oblique angle; pictures taken at oblique angles are prone to misinterpretation of curve magnitude

This article is the second article in a two-part review on lumbar facet joint pathology. In this review, we discuss the current concepts and controversies regarding the proper diagnosis and management of patients presenting with presumed facet-mediated lower back pain. All efforts were made to include the most relevant literature from the fields of radiology, orthopaedics, physiatry, and pain management. Our focus in this article is on presenting the evidence supporting or refuting the most commonly employed injection-based therapies for facet-mediated lower back pain

We present a two-part review article on the current state of knowledge of lumbar facet joint pathology. This first article discusses the functional anatomy, biomechanics, and radiological grading systems currently in use in clinical practice and academic medicine. Facet joint degeneration is presented within the larger context of degenerative disc disease to enable the reader to better understand the anatomical changes underlying facet-mediated lower back pain. Other less-common, but equally important etiologies of lumbar facet joint degeneration are reviewed. The existing grading systems are discussed with specific reference to the reliability of CT and MR imaging in the diagnosis of lumbar facet osteoarthritis. It is hoped that this discussion will stimulate debate on how best to improve the diagnostic reliability of these tests so as to improve both operative and non-operative treatment outcomes