Young Lu

Dysphagia following anterior cervical spinal surgery: A systematic review

Dysphagia is a common complication of anterior surgery of the cervical spine. The incidence of post-operative dysphagia may be as high as 71% within the first two weeks after surgery, but gradually decreases during the following months. However, 12% to 14% of patients may have some persistent dysphagia one year after the procedure. It has been shown that female gender, advanced age, multilevel surgery, longer operating time and severe pre-operative neck pain may be risk factors. Although the aetiology remains unclear and is probably multifactorial, proposed causes include oesophageal retraction, prominence of the cervical plate and prevertebral swelling. Recently, pre-operative tracheal traction exercises and the use of retropharyngeal steroids have been proposed as methods of reducing post-operative dysphagia. We performed a systematic review to assess the incidence, aetiology, risk factors, methods of assessment and management of dysphagia following anterior cervical spinal surgery.

Nonoperative Management of Discogenic Back Pain: A Systematic Review

Study Design. Systematic review of the literature. Objective. A systematic evaluation of the literature was performed to investigate current nonoperative management of the treatment of discogenic low back pain. Summary of Background Data. Back pain is a major health care concern with up to 39% being discogenic in origin according to one study. Nonoperative therapy is likely to be the initial treatment strategy for discogenic low back pain. Methods. PubMed, EMBASE, and Cochrane Central Register of Controlled Trials were searched for clinical studies evaluating nonoperative methods of treating discogenic back pain that were published between 2000 and 2012. Only prospective randomized controlled studies that compared a nonsurgical intervention with sham or placebo therapy were included. After removal of duplicate citations, a total of 226 articles were initially identified from the search terms. From these, we identified 11 randomized controlled trials (RCTs) from which data analysis was performed. Results. The 11 RCTs investigated traction therapy, injections, and ablative techniques. Results from 5 RCTs investigating methylene blue injection, steroid injection, ramus communicans ablation, intradiscal electrothermal therapy, and biacuplasty favored intervention over sham therapy. However, results from the study on methylene blue injections have not been replicated in other RCTs. Evaluation of the selection criteria used in the studies on ramus communicans ablation and intradiscal biacuplasty and a stratified analysis of results from the RCTs on intradiscal electrothermal therapy casts doubt on whether the conclusions from these RCTs can be applied to the general patient population with discogenic pain. Conclusion. There are few high-quality studies evaluating nonoperative treatments for reducing discogenic low back pain. Although conclusions from several studies favor intervention over sham, it is unclear whether these interventions confer stable long-term benefit. There is some promise in newer modalities such as biacuplasty; however, more inclusive studies need to be performed. Level of Evidence: 2

Chronic Ingestion of Advanced Glycation End Products Induces Degenerative Spinal Changes and Hypertrophy in Aging Pre-Diabetic Mice

Intervertebral disc (IVD) degeneration and pathological spinal changes are major causes of back pain, which is the top cause of global disability. Obese and diabetic individuals are at increased risk for back pain and musculoskeletal complications. Modern diets contain high levels of advanced glycation end products (AGEs), cyto-toxic components which are known contributors to obesity, diabetes and accelerated aging pathologies. There is little information about potential effects of AGE rich diet on spinal pathology, which may be a contributing cause for back pain which is common in obese and diabetic individuals. This study investigated the role of specific AGE precursors (e.g. methylglyoxal-derivatives (MG)) on IVD and vertebral pathologies in aging C57BL6 mice that were fed isocaloric diets with standard (dMG+) or reduced amounts of MG derivatives (dMG-; containing 60-70% less dMG). dMG+ mice exhibited a pre-diabetic phenotype, as they were insulin resistant but not hyperglycemic. Vertebrae of dMG+ mice displayed increased cortical-thickness and cortical-area, greater MG-AGE accumulation and ectopic calcification in vertebral endplates. IVD morphology of dMG+ mice exhibited ectopic calcification, hypertrophic differentiation and glycosaminoglycan loss relative to dMG- mice. Overall, chronic exposure to dietary AGEs promoted age-accelerated IVD degeneration and vertebral alterations involving ectopic calcification which occurred in parallel with insulin resistance, and which were prevented with dMG- diet. This study described a new mouse model for diet-induced spinal degeneration, and results were in support of the hypothesis that chronic AGE ingestion could be a factor contributing to a pre-diabetic state, ectopic calcifications in spinal tissues, and musculoskeletal complications that are more generally known to occur with chronic diabetic conditions.

Utilization trends of cervical artificial disc replacement after FDA approval compared with anterior cervical fusion: adoption of new technology.

Study Design. Epidemiologic study. Objective. To compare the utilization of anterior cervical discectomy and fusion (ACDF) versus cervical disc arthroplasty (CDA) in terms of patient and hospital characteristics during the 3 years after Food and Drug Administration (FDA) approval of CDA devices in 2007. Summary of Background Data. There was a surge in CDA adoption in the 3 years prior to FDA approval of CDA devices in 2007. However, utilization trends of CDA versus ACDF since the FDA approval are unknown. Methods. The Nationwide Inpatient Sample database was used to identify CDA and ACDF procedures performed in the United States in the 3 years after FDA approval of CDA devices (2008–2010). The frequencies of CDA and ACDF were estimated, stratified by patient and hospital characteristics. Average length of hospital stay and total charges and costs were estimated. Multivariable analysis was performed to identify patient and hospital characteristics associated with CDA utilization. Results. In the 3 years after FDA approval of cervical disc devices, population-adjusted growth rates for CDA and ACDF were 4.9% and 11.8%, respectively (P = 0.6977). Female, African American and Medicaid patients were less likely to receive CDA. CDA was less likely to be performed in patients with cervical spondylotic changes and more likely to be performed in younger and healthier patients. CDA was less likely to be performed in the Midwestern United States or in public hospitals. Conclusion. The prevalence of CDA increased in the 3 years after FDA approval with a growth rate that is approximately twice than that for ACDF. Although there seems to be CDA adoption, CDA growth seemed to have reached a plateau and ACDF still remained the dominant surgical strategy for cervical disc disease. Possible regional, racial, and sex disparities in CDA utilization and a more strict approach in the selection of CDA over traditional ACDF may have impeded rapid adoption of CDA. Level of Evidence: 3

Three-dimensional Intraoperative Imaging Modalities in Orthopaedic Surgery: A Narrative Review.

Intraoperative imaging and navigation systems have revolutionized orthopaedic surgery for the spine, joints, and orthopaedic trauma. Imaging modalities such as the isocentric C-arm, O-arm imaging, and intraoperative MRI or navigation systems allow the visualization of surgical instruments and implants relative to a three-dimensional CT image or MRI. Studies show that these technologies lower the rates of implant misplacement and inadequate fracture reduction, thereby improving surgical outcomes and reducing reoperation rates. An additional benefit is reduced radiation exposure compared with that for conventional fluoroscopy. Concerns surrounding adoption of these technologies include cost and increased operating times, but improvements in design and protocol may improve the integration of these imaging modalities into the operating room.

Utilization trends of cervical artificial disc replacement during the FDA investigational device exemption clinical trials compared to anterior cervical fusion

While anterior cervical discectomy and fusion (ACDF) is the gold standard surgical treatment for cervical disc disease, concerns regarding adjacent segment degeneration lead to the development of cervical disc arthroplasty (CDA). This study compares the utilization trends of CDA versus ACDF during the period of the Food and Drug Administration Investigational Device Exemption clinical trials from 2004 to 2007. The Healthcare Cost and Utilization Project Nationwide Inpatient Sample database was used to identify CDA and ACDF procedures performed in the USA between 2004 and 2007. The prevalence of CDA and ACDF procedures was estimated and stratified by age, sex, diagnosis, census region, payor class, and hospital characteristics. The average length of hospital stay, total charges, and costs were also estimated. The number of CDA surgeries significantly increased annually from 2004 to 2007 and mostly took place at urban non-teaching hospitals. There were no regional differences between CDA and ACDF utilization. There was no difference between sex or admission type between CDA and ACDF patients. ACDF patients were older and had more diabetes, hypertension, and chronic obstructive pulmonary disease. CDA patients were more likely to be discharged home and had shorter hospital stays but had a higher rate of deep venous thrombosis than ACDF patients. Significantly more CDA patients had private insurance while more ACDF patients had Medicare. The average cost was higher for ACDF than CDA. While ACDF dominated surgical intervention for cervical disc disease during the trial period, CDA utilization increased at a significantly greater rate suggesting rapid early adoption.

Detrimental effects of discectomy on intervertebral disc biology can be decelerated by growth factor treatment during surgery: a large animal organ culture model

BACKGROUND CONTEXT Lumbar discectomies are common surgical interventions that treat radiculopathy by removing herniated and loose intervertebral disc (IVD) tissues. However, remaining IVD tissue can continue to degenerate resulting in long-term clinical problems. Little information is available on the effects of discectomy on IVD biology. Currently, no treatments exist that can suspend or reverse the degeneration of the remaining IVD. PURPOSE To improve the knowledge on how discectomy procedures influence IVD physiology and to assess the potential of growth factor treatment as an augmentation during surgery. STUDY DESIGN To determine effects of discectomy on IVDs with and without transforming growth factor beta 3 (TGFβ3) augmentation using bovine IVD organ culture. METHODS This study determined effects of discectomy with and without TGFβ3 injection using 1-, 6-, and 19-day organ culture experiments. Treated IVDs were injected with 0.2 μg TGFβ3 in 20 μL phosphate-buffered saline+bovine serum albumin into several locations of the discectomy site. Cell viability, gene expression, nitric oxide (NO) release, IVD height, aggrecan degradation, and proteoglycan content were determined. RESULTS Discectomy significantly increased cell death, aggrecan degradation, and NO release in healthy IVDs. Transforming growth factor beta 3 injection treatment prevented or mitigated these effects for the 19-day culture period. CONCLUSIONS Discectomy procedures induced cell death, catabolism, and NO production in healthy IVDs, and we conclude that post-discectomy degeneration is likely to be associated with cell death and matrix degradation. Transforming growth factor beta 3 injection augmented discectomy procedures by acting to protect IVD tissues by maintaining cell viability, limiting matrix degradation, and suppressing NO. We conclude that discectomy procedures can be improved with injectable therapies at the time of surgery although further in vivo and human studies are required.

The effect of increasing pedicle screw size on thoracic spinal canal dimensions: an anatomic study.

Study Design. Anatomic study. Objective. To determine whether the thoracic spinal canal diameter decreases when the pedicle is allowed to expand with increasing screw diameter. To observe whether osseous breach occurs medially or laterally. Summary of Background Data. Insertion of a pedicle screw that is larger in diameter than that of the native pedicle has been shown to expand the pedicle and increase biomechanical fixation strength. With this technique, there is concern for medial expansion of the pedicle causing decrease in spinal canal diameter, especially in the concavity of scoliosis, resulting in spinal cord compression. Also, large pedicle screws that are inserted correctly may still cause undetected medial bony breach during surgery. Methods. A total of 162 pedicles from 81 thoracic vertebrae (T1–T12) of 7 fresh-frozen adult cadavers were analyzed. After undertapping the pedicle by 1 mm, pedicle screws were inserted in increasing diameter (range, 4.0–9.5 mm) bilaterally until there was an osseous breach in the pedicle. A total of 938 screws were used. Transverse spinal canal diameter and pedicle circumference were measured (in millimeters) before and after each pedicle screw placement. Photographs and fluoroscopic images of representative specimens were obtained for visual assessment. Results. The average transverse spinal canal diameter was 17.7 mm. The average transverse canal diameter with the largest screw inserted before bony breach was detected was 17.6 mm (P = 0.92). The average diameter of the largest screw inserted before breach was 6.9 mm. Pedicle circumference increased from 41.8 mm before screw placement to 43.4 mm at maximal expansion before bony breach with the next sized screw. Twenty-eight pedicles did not break with 9.5-mm-diameter screws. There were 133 lateral and 1 medial breaches. Conclusion. Increasing pedicle screw size caused pedicle expansion laterally but did not significantly alter transverse spinal canal dimensions. When there was an osseous breach, most were lateral (99.3%). Level of Evidence: N/A

Hemostatic Agents in Spine Surgery: A Critical Analysis Review

Blood loss during spine surgery is one of the most difficult challenges facing the surgeon, with effects ranging from decreased visualization of the operative field to life-threatening hemorrhage. Specific considerations for intraoperative bleeding include the potential for development of acute stroke from vertebral artery transection to spinal cord ischemia. Additionally, the need for perioperative transfusion of blood products has been associated with longer hospital stays and increased cost1. Management of blood loss begins in the preoperative period with discontinuation of medications known to increase the risk of bleeding, including aspirin, other nonsteroidal anti-inflammatory medications, and anticoagulants. The reasons for taking these medications and their discontinuation should be discussed with both the patient and the patient’s primary care physician or cardiologist. At the time of the operation, a collaborative effort between the anesthesiologist and the surgeon is undertaken to manage appropriate hemostasis. This …

Risk of Osteonecrosis among Persons with Osteoarthritis of the Knee: Findingsfrom the UK based General Practice Research Database

Anterior Cervical Discectomy and Fusion (ACDF) is a widely utilized surgical treatment for cervical disc disease. Despite success of ACDF, concerns regarding adjacent segment degeneration led to the design and development of cervical disc arthroplasty (CDA). We performed a systematic review of studies comparing the efficacy and safety profile of CDA versus ACDF. We searched databases Pubmed, EMBASE and Cochrane Central Register of Controlled Trials (CENTRAL) for prospective randomized controlled studies comparing CDA with ACDF with at least 24-month follow-up. Studies were evaluated for level of bias. Data regarding clinical outcomes, postoperative kinematic changes, procedure or device related adverse events and types and rates of secondary surgeries were extracted. A total of 142 articles were retrieved of which 8 articles satisfied the inclusion and exclusion criteria. These eight studies cover five different disc devices (BRYAN, PRESTIGE, ProDisc-C, Kineflex|C and Porous Coated Motion). There are significant differences in some patient reported clinical outcomes favoring arthroplasty over ACDF. Arthroplasty also preserved motion at the operated site while fusion reduced range of motion at the fused segments. The type and rate of adverse events, postoperative complications and secondary surgeries are similar between the two groups. The rate of surgeries for adjacent level degeneration is similar between CDA and ACDF. Cervical Disc Arthroplasty is a viable alternative procedure in the surgical management of cervical disc disease with similar safety profiles and at least equivalent and possibly superior clinical outcomes compared to Anterior Cervical Discectomy and Fusion. There does not appear to be significant differences in reoperation rates for adjacent level degeneration between the two procedure types. Future long-term follow up studies are needed to make a more robust conclusion on the overall effectiveness of CDA.