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 (TGFß3) augmentation using bovine IVD organ culture. METHODS: This study determined effects of discectomy with and without TGFß3 injection using 1-, 6-, and 19-day organ culture experiments. Treated IVDs were injected with 0.2 µg TGFß3 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.

Analysis of the techniques for thoracic- and lumbar-level localization during posterior spine surgery and the occurrence of wrong-level surgery: results from a national survey.

BACKGROUND CONTEXT: Despite the frequency with which surgeons perform posterior spinal surgery and the precautions against wrong-site surgery, operations on incorrect levels still occur. Wrong-level exposure is documented in 0.32% to 15% of cases. Additionally, there is little consensus as to what is the most accurate method for localizing the correct spinal level. PURPOSE: The purpose of this study is to investigate the most commonly used localization methods and their association with wrong-level surgery, to determine the prevalence of wrong-level localization, and to identify circumstances commonly associated with wrong-level surgery, and to offer recommendations that may reduce the incidence of these errors. STUDY DESIGN/SETTING: This was an online survey study that was distributed to North American Spine Society (NASS) members (including both orthopedic surgeons and neurosurgeons). The survey was sent as a Web link within an e-mail. PATIENT SAMPLE: A total of 2,338 surgeons received the survey, 532 opened the survey, and 173 completed it (7.4% response rate). The survey was only sent once, as recommended by NASS. Of those that responded, 72% (124 of 173) were orthopedic surgeons, 28% (49 of 173) were neurosurgeons, and 73% (126 of 173) were spine fellowship trained. OUTCOME MEASURES: We sought to investigate self-reported localization methods that are most commonly used (both anatomic landmarks and imaging techniques), the prevalence of wrong-level surgery, and any correlations between localization method and wrong-level surgery. METHODS: An eight-question anonymous survey was distributed to members of NASS, including orthopedic surgeons and neurosurgeons. There was no pilot testing or validation performed for this survey. The survey was sent as a Web link within an e-mail. Some questions asked surgeons to select as many responses as applicable, and others allowed surgeons to describe in detail any cases of wrong-level surgery. This study neither requires nor receives funding; additionally, no conflicts of interests were reported. RESULTS: Fluoroscopy was the most commonly used imaging technique for thoracic and lumbar surgeries (89% and 86%, respectively), followed by plain radiographs (54% and 58%, respectively). Surgeons were allowed to select as many responses as applicable, and 76 surgeons reported using both plain radiographs and fluoroscopy. The facet joint with corresponding pedicle was the most commonly used anatomic landmark for localization of thoracic and lumbar surgeries (67% and 59%, respectively), followed by the spinous process (49% and 52%, respectively). Sixty-eight percent of surgeons admitted to wrong-level localization, some of which were rectified intraoperatively, during their careers. Fifty-six percent of these surgeons reported using plain radiographs and 44% used fluoroscopy when the errors occurred. Common sources of preoperative errors included failure to visualize known reference points, recognize unconventional spinal anatomy, and adequately visualize the level because of large body habitus. Common sources of intraoperative errors included poor communication, failure to relocalize after exposure, and poor counting methods. CONCLUSIONS: Despite the variety of localization modalities, most surgeons use only a few. Whereas wrong-level localization is relatively rare, the ideal frequency is never. There is no standard approach that will entirely eliminate these mistakes; however, using a localization time out and increasing awareness of common sources of error may help decrease the incidence of wrong-level spine surgery.

Genetic polymorphisms associated with intervertebral disc degeneration.

BACKGROUND CONTEXT: Disc degeneration (DD) is a multifaceted chronic process that alters the structure and function of the intervertebral discs and can lead to painful conditions. The pathophysiology of degeneration is not well understood, but previous studies suggest that certain genetic polymorphisms may be important contributing factors leading to an increased risk of DD. PURPOSE: To review the genetic factors in DD with a focus on polymorphisms and their putative role in the pathophysiology of degeneration. Elucidating the genetic components that are associated with degeneration could provide insights into the mechanism of the process. Furthermore, defining these relationships and eventually using them in a clinical setting may allow an identification and early intervention for those who are at a high risk for painful DD. STUDY DESIGN: Literature review. METHODS: This literature review focused on the studies concerning genetic polymorphisms and their associations with DD. RESULTS: Genetic polymorphisms in 20 genes have been analyzed in association with DD, including vitamin D receptor, growth differentiation factor 5 (GDF5), aggrecan, collagen Types I, IX, and XI, fibronectin, hyaluronan and proteoglycan link protein 1 (HAPLN1), thrombospondin, cartilage intermediate layer protein (CILP), asporin, MMP1, 2, and 3, parkinson protein 2, E3 ubiquitin protein ligase (PARK2), proteosome subunit ß type 9 (PSMB9), tissue inhibitor of metalloproteinase (TIMP), cyclooxygenase-2 (COX2), and IL1α, IL1ß, and IL6. Each genetic polymorphism codes for a protein that has a functional role in the pathogenesis of DD. CONCLUSIONS: There are known associations between several genetic polymorphisms and DD. Of the 20 genes analyzed, polymorphisms in vitamin D receptor, aggrecan, Type IX collagen, asporin, MMP3, IL1, and IL6 show the most promise as functional variants. Genetic studies are crucial for understanding the mechanism of the degeneration. This genetic information could eventually be used as a predictive model for determining a patient's risk for symptomatic DD.