Static vs. Expandable PEEK Interbody Cages: A Comparison of One-Year Clinical and Radiographic Outcomes for One-Level TLIF

Introduction: Degenerative spine disease is a disabling condition affecting many worldwide. Transoforaminal lumbar interbody fusion (TLIF) procedures help stabilize the spine, while improving back and/or leg pain. With the introduction of new implant designs and modifications, focus has shifted to optimizing spinopelvic alignment, fusion rates, and more. This study aims to explore the effect of static versus expandable polyetheretherketone (PEEK) cages on patient-reported outcomes (PROMs) and radiographic outcomes (subsidence, disk height, and alignment parameters). Materials/Methods: A retrospective cohort study was conducted using a database of patients in a single, high volume academic center. Patient outcomes were obtained from charts and radiographic outcomes were measured using standing, lateral radiographs. Data were analyzed using mean sample t-tests or categorical chi-squared tests, and multiple linear regression where appropriate. Results: Our results showed improved Oswestry Disability Index (ODI) scores perioperatively in the expandable cage group compared to the static cage group at the three-month and one-year time periods. In addition, there were a significantly greater proportion of patients that reached minimal clinically important difference (MCID) in the expandable group compared to the static cage group. There were no significant changes in subsidence or alignment parameters between the two groups at the one-year time period. Conclusion: Overall, our results show that TLIF patients treated with expandable PEEK cages had significantly greater improvement in one-year outcomes compared to patients with static cages. Expandable cages confer the advantage of more precise insertion into the intervertebral disk space, while providing a way to tailor the cage height for better distraction and spinal alignment. Further prospective studies are warranted to get a better idea of the impact of interbody design on clinical/radiographic outcomes

Quantitative Assessment of the Anatomical Footprint of the C1 Pedicle Relative to the Lateral Mass: A Guide for C1 Lateral Mass Fixation

Study Design: Anatomic study. Objectives: To determine the relationship of the anatomical footprint of the C1 pedicle relative to the lateral mass (LM). Methods: Anatomic measurements were made on fresh frozen human cadaveric C1 specimens: pedicle width/height, LM width/height (minimum/maximum), LM depth, distance between LM’s medial aspect and pedicle’s medial border, distance between LM’s lateral aspect to pedicle’s lateral border, distance between pedicle’s inferior aspect and LM’s inferior border, distance between arch’s midline and pedicle’s medial border. The percentage of LM medial to the pedicle and the distance from the center of the LM to the pedicle’s medial wall were calculated. Results: A total of 42 LM were analyzed. The C1 pedicle’s lateral aspect was nearly confluent with the LM’s lateral border. Average pedicle width was 9.0 ± 1.1 mm, and average pedicle height was 5.0 ± 1.1 mm. Average LM width and depth were 17.0 ± 1.6 and 17.2 ± 1.6 mm, respectively. There was 6.9 ± 1.5 mm of bone medial to the medial C1 pedicle, which constituted 41% ± 9% of the LM’s width. The distance from C1 arch’s midline to the medial pedicle was 13.5 ± 2.0 mm. The LM’s center was 1.6 ± 1 mm lateral to the medial pedicle wall. There was on average 3.5 ± 0.6 mm of the LM inferior to the pedicle inferior border. Conclusions: The center of the lateral mass is 1.6 ± 1 mm lateral to the medial wall of the C1 pedicle and approximately 15 mm from the midline. There is 6.9 ± 1.5 mm of bone medial to the medial C1 pedicle. Thus, the medial aspect of C1 pedicle may be used as an anatomic reference for locating the center of the C1 LM for screw fixation

The Use of Bone Morphogenetic Protein in the Intervertebral Disk Space in Minimally Invasive Transforaminal Lumbar Interbody Fusion

Study Design: Retrospective Cohort. Objective: The objective of this study was to characterize one surgeon’s experience over a 10-year period using rhBMP-2 in the disk space for minimally invasive transforaminal lumbar interbody fusion (MIS TLIF). Summary of Background Data: MIS TLIF has been utilized as a technique for decreasing patients’ immediate postoperative pain, decreasing blood loss, and shortened hospital stays. Effectiveness and complications of rhBMP-2’s use in the disk space is limited because of its off-label status. Methods: Retrospective analysis of consecutive MIS TLIFs performed by senior author between 2004 and 2014. rhBMP-2 was used in the disk space in all cases. Patients were stratified based on the dose of rhBMP-2 utilized. Patients had 9 to 12 month computerized tomography scan to evaluate for bony fusion and continued follow-up for 18 months. Results: A total of 688 patients underwent a MIS TLIF. A medium kit of rhBMP-2 was utilized in 97 patients, and small kit was used in 591 patients. Fusion rate was 97.9% and this was not different between the 2 groups with 96/97 patients fusing in the medium kit group and 577/591 patients fusing in the small kit group. Five patients taken back to the operating room for symptomatic pseudoarthrosis, 4 reoperated for bony hyperostosis, and 10 radiographic pseudoarthroses that did not require reoperation. A statistically significant difference in the rate of foraminal hyperostosis was found when using a medium sized kit of rhBMP-2 was 4.12% (4/97 patients), compared with a small kit (0/591 patients, P=0.0004). Conclusions: Utilization of rhBMP-2 in an MIS TLIF leads to high fusion rate (97.9%), with an acceptable complication profile. The development of foraminal hyperostosis is a rare complication that only affected 0.6% of patients, and seems to be a dose related complication, as this complication was eliminated when a lower dose of rhBMP-2 was utilized

Pathophysiology, diagnosis, and treatment of spinal meningoceles and arachnoid cysts

Though the nomenclature regarding spinal arachnoid cysts and meningoceles is confusing and sometimes overlapping, spinal arachnoid cysts and meningoceles are distinct entities with different presentations and etiologies. Meningoceles are usually congenital lesions discovered at infancy with a high incidence of associated anomalies. Spinal arachnoid cysts are most often asymptomatic but can cause nerve root and/or cord compression. We review the presentation, pathophysiology, and management of these lesions

Corticosteroid Administration to Prevent Complications of Anterior Cervical Spine Fusion: A Systematic Review.

Study Design: Systematic review. Objectives: Anterior cervical approach is associated with complications such as dysphagia and airway compromise. In this study, we aimed to systematically review the literature on the efficacy and safety of corticosteroid administration as a preventive measure of such complications in anterior cervical spine surgery with fusion. Methods: Following a systematic literature search of MEDLINE, Embase, and Cochrane databases in July 2016, all comparative human studies that evaluated the effect of steroids for prevention of complications in anterior cervical spine surgery with fusion were included, irrespective of number of levels and language. Risk of bias was assessed using MINORS (Methodological Index for Non-Randomized Studies) checklist and Cochrane Back and Neck group recommendations, for nonrandomized and randomized studies, respectively. Results: Our search yielded 556 articles, of which 9 studies (7 randomized controlled trials and 2 non-randomized controlled trials) were included in the final review. Dysphagia was the most commonly evaluated complication, and in most studies, its severity or incidence was significantly lower in the steroid group. Although prevertebral soft tissue swelling was less commonly assessed, the results were generally in favor of steroid use. The evidence for airway compromise and length of hospitalization was inconclusive. Steroid-related complications were rare, and in both studies that evaluated the fusion rate, it was comparable between steroid and control groups in long-term follow-up. Conclusions: Current literature supports the use of steroids for prevention of complications in anterior cervical spine surgery with fusion. However, evidence is limited by substantial risk of bias and small number of studies reporting key outcomes

Indirect costs associated with surgery for low back pain-a secondary analysis of clinical trial data.

This study examines the indirect costs associated with surgery for axial low back pain using data obtained from a prospective multicenter clinical trial that compared Charité artificial disc replacement with anterior lumbar interbody fusion using iliac crest bone graft. While 75% of study subjects reported full- or part-time employment prior to surgery, this percentage dropped to 45% at 6 weeks postoperatively. Return to preoperative employment levels occurred at approximately 6 months postoperatively. Two years after surgery, employment levels were 16% higher than preoperative levels. Lost productivity related to absenteeism resulted in lost wages averaging $2884 per patient during the first postoperative year. Although short-term indirect costs of surgery are substantial from a societal perspective, the higher employment rate at 2 years suggests a long-term economic benefit. The findings demonstrate the significant, though not surprising, impact of spinal disability on productivity, and the importance of including measurement of lost productivity and return to work in the economic evaluation of related interventions