International classification of disease clinical modification 9 modeling of a patient comorbidity score predicts incidence of perioperative complications in a nationwide inpatient sample assessment of complications in spine surgery.

OF BACKGROUND DATA: A patient comorbidity score (RCS) was developed from a prospective study of complications occurring in spine surgery patients. OBJECTIVE: To validate the RCS, we present an International Classification of Disease Clinical Modification (ICD-CM)-9 model of the score and correlate the score with complication incidence in a group of patients from the Nationwide Inpatient Sample database. We compare the predictive value of the score with the Charlson index. STUDY DESIGN: We conducted a retrospective assessment of Nationwide Inpatient Sample patients undergoing cervical or thoracolumbar spine surgery for degenerative pathology from 2002 to 2009. METHODS: We generated an ICD-9-CM coding-based model of our prospectively derived RCS, categorizing diagnostic codes to represent relevant comorbidities. Multivariate models were constructed to eliminate the least significant variables. ICD-9-CM coding was also used to calculate a Charlson comorbidity score for each patient. The accuracy of the RCS was compared with the Charlson index through the use of a receiver-operating curve. RESULTS: A total of 352,535 patients undergoing 369,454 spine procedures for degenerative disease were gathered. Hypertension and hyperlipidemia were the most common comorbidities. Cervical procedures resulted in 8286 complications (4.50%), whereas thoracolumbar procedures produced 25,118 complications (13.55%). Increasing RCS correlated linearly with increasing complication incidence (odds ratio [OR] 1.11; 95% confidence interval [CI], 1.10-1.13; P<0.0001). Logistic regression revealed that neurological deficit, cardiac conditions, and drug or alcohol use had greatest association with complication occurrence. The Charlson index also correlated with complication occurrence in both cervical (OR 1.25; 95% CI, 1.23-1.27) and thoracolumbar (OR 1.11; 95% CI, 1.10-1.12) patient groups. Receiver-operating curve analysis allowed a comparison of accuracy of the indices by comparing predictive values. The RCS performed as well as the Charlson index in predicting complication occurrence in both cervical and thoracic spine patients. CONCLUSIONS: ICD-9-based modeling validated that RCS correlates with complication occurrence. The RCS performed as well as the Charlson index in predicting risk of complication in spine patients.

Hypoxia activates the notch signaling pathway in cells of the intervertebral disc: implications in degenerative disc disease.

OBJECTIVE: To investigate whether hypoxia regulates Notch signaling, and whether Notch plays a role in intervertebral disc cell proliferation. METHODS: Reverse transcription-polymerase chain reaction and Western blotting were used to measure expression of Notch signaling components in intervertebral disc tissue from mature rats and from human discs. Transfections were performed to determine the effects of hypoxia and Notch on target gene activity. RESULTS: Cells of the nucleus pulposus and annulus fibrosus of rat disc tissue expressed components of the Notch signaling pathway. Expression of Notch-2 was higher than that of the other Notch receptors in both the nucleus pulposus and annulus fibrosus. In both tissues, hypoxia increased Notch1 and Notch4 messenger RNA (mRNA) expression. In the annulus fibrosus, mRNA expression of the Notch ligand Jagged1 was induced by hypoxia, while Jagged2 mRNA expression was highly sensitive to hypoxia in both tissues. A Notch signaling inhibitor, L685458, blocked hypoxic induction of the activity of the Notch-responsive luciferase reporters 12xCSL and CBF1. Expression of the Notch target gene Hes1 was induced by hypoxia, while coexpression with the Notch-intracellular domain increased Hes1 promoter activity. Moreover, inhibition of Notch signaling blocked disc cell proliferation. Analysis of human disc tissue showed that there was increased expression of Notch signaling proteins in degenerated discs. CONCLUSION: In intervertebral disc cells, hypoxia promotes expression of Notch signaling proteins. Notch signaling is an important process in the maintenance of disc cell proliferation, and thus offers a therapeutic target for the restoration of cell numbers during degenerative disc disease.

Complications related to instrumentation in spine surgery: a prospective analysis.

OBJECT: Prospective examination of perioperative complications in spine surgery is limited in the literature. The authors prospectively collected data on patients who underwent spinal fusion at a tertiary care center and evaluated the effect of spinal fusion and comorbidities on perioperative complications. METHODS: Between May and December 2008 data were collected prospectively in 248 patients admitted to the authors' institution for spine surgery. The 202 patients undergoing spine surgery with instrumentation were further analyzed in this report. Perioperative complications occurring within the initial 30 days after surgery were included. All adverse occurrences, whether directly related to surgery, were included in the analysis. RESULTS: Overall, 114 (56.4%) of 202 patients experienced at least one perioperative complication. Instrumented fusions were associated with more minor complications (p = 0.001) and more overall complications (0.0024). Furthermore, in the thoracic and lumbar spine, complications increased based on the number of levels fused. Advanced patient age and certain comorbidities such as diabetes, cardiac disease, or a history of malignancy were also associated with an increased incidence of complications. CONCLUSIONS: Using a prospective methodology with a broad definition of complications, the authors report a significantly higher perioperative incidence of complications than previously indicated after spinal fusion procedures. Given the increased application of instrumentation, especially for degenerative disease, a better estimate of clinically relevant surgical complications could aid spine surgeons and patients in an individualized complication index to facilitate a more thorough risk-benefit analysis prior to surgery.

Incidence of early complications in cervical spine surgery and relation to preoperative diagnosis: a single-center prospective study.

STUDY DESIGN: Prospective observational cohort study. OBJECTIVE: To determine the incidence of early postoperative complications in patients undergoing cervical spine surgery and its correlation with preoperative diagnosis. SUMMARY OF BACKGROUND DATA: The reported incidence of complications and adverse events in cervical spine surgery is highly variable. Inconsistent definitions and varying methodologies have made the interpretation of earlier reports difficult. No large study has analyzed the overall early morbidity of cervical spine surgery in a prospective fashion or attempted to correlate preoperative diagnosis and comorbidities with perioperative complications. METHODS: Data on 121 consecutive patients, who underwent cervical spine surgery at the Thomas Jefferson University Hospital from May to December 2008, was prospectively collected. Complication definition and gradations of complication severity were validated by a survey of spine surgeons and spine surgery patients. An independent assessor prospectively audited complication incidence in the patient cohort. Data on diagnosis, comorbidities, BMI, complications, and length of stay were prospectively collected and assessed using stepwise multivariate analysis. RESULTS: The overall incidence of early complications was 47.1% with a 40.5% incidence of minor complications and an 18.2% incidence of major complications. Major complication incidence was greater in cases of infection (20.0%) and spinal oncologic procedures (30.0%), although this difference was not of statistical significance (P=0.07). Total number of complications recorded was greater in cases of infection and neoplasm (P=0.05). CONCLUSIONS: Complications in cervical spine procedures occurred most frequently in cases involving trauma and spinal oncologic procedures. This study illustrates that the incidence of early complications in cervical spine procedures is greater than appreciated earlier. This difference likely arises owing to the use of a broad definition of perioperative complications, elimination of recall bias through use of a prospective assessment, and overall case complexity. Accurate assessment of the incidence of early complications in cervical spine surgery is important for patient counseling and in design of prospective quality improvement programs.

Preoperative diagnosis and early complications in thoracolumbar spine surgery: a single center prospective study.

STUDY DESIGN: Prospective observational cohort study. OBJECTIVE: To determine the incidence of early complications with thoracolumbar spine surgery and its correlation with preoperative diagnosis. SUMMARY OF BACKGROUND DATA: The reported incidence of early complications associated with thoracolumbar surgery is highly variable. Varying definitions of what constitutes a "complication" and varying study methodologies make evaluation and comparison of the literature difficult. No large study has investigated the effect of preoperative diagnosis and patient comorbidities on early postoperative complications in thoracolumbar surgery. METHODS: One-hundred twenty-eight consecutive patients who underwent thoracolumbar surgery by the neurosurgical service at the Thomas Jefferson University Hospital were prospectively entered into a central database from May to December 2008. An earlier-described, binary definition of major and minor complication was used. Data on preoperative diagnosis, comorbidities, body mass index, surgical procedure, length of stay (LOS), and early complication was examined using χ and time-to-discharge survival analysis. RESULTS: The overall complication incidence was 59.4%, with a minor complication incidence of 52.3% and a major complication incidence of 24.2%. The highest incidences of complications occurred in patients with the diagnosis of infection and tumor, where incidence exceeded 70%; this difference did not achieve statistical significance. The overall median LOS was 7 days; LOS was longer in patients with traumatic pathology (17 d) and patients with neoplastic pathology (14 d) (P<0.05). CONCLUSIONS: A higher incidence of complications than earlier studies was noted. A trend toward higher complication incidence in patients with infectious or neoplastic disease was observed. The severity of patient pathology, the broader definitions of complication used, and the elimination of recall bias by the use of a prospective study design accounts for the higher incidence of complications reported in this series. However, a large, prospective study using clear definitions is needed to elucidate the true incidence of early complications in thoracolumbar surgery.

Emerging clinical imaging techniques for cerebral cavernous malformations: a systematic review.

Cerebral cavernous malformations (CCMs) are divided into sporadic and familial forms. For clinical imaging, T2-weighted gradient-echo sequences have been shown to be more sensitive than conventional sequences. Recently more advanced imaging techniques such as high-field and susceptibility-weighted MR imaging have been employed for the evaluation of CCMs. Furthermore, diffusion tensor imaging and functional MR imaging have been applied to the preoperative and intraoperative management of these lesions. In this paper, the authors attempt to provide a concise review of the emerging imaging methods used in the clinical diagnosis and treatment of CCMs.

Deep brain stimulation in the management of disorders of consciousness: a review of physiology, previous reports, and ethical considerations.

Patients suffering from disorders of consciousness constitute a population that exists largely outside of the daily practice patterns of neurosurgeons. Historically, treatment has focused on nursing and custodial issues with limited neurosurgical intervention. Recently, however, deep brain stimulation has been explored to restore cognitive and physical function to patients in minimally conscious states. In this article, the authors characterize the physiological mechanisms for the use of deep brain stimulation in persistently vegetative and minimally conscious patients, review published cases and associated ethical concerns, and discuss future directions of this technology.

Adult scoliosis surgery outcomes: a systematic review.

OBJECT: Appreciation of the optimal management of skeletally mature patients with spinal deformities requires understanding of the natural history of the disease relative to expected outcomes of surgical intervention. Appropriate outcome measures are necessary to define the surgical treatment. Unfortunately, the literature lacks prospective randomized data. The majority of published series report outcomes of a particular surgical approach, procedure, or surgeon. The purpose of the current study was to systematically review the present spine deformity literature and assess the available data on clinical and radiographic outcome measurements. METHODS: A systematic review of MEDLINE and PubMed databases was performed to identify articles published from 1950 to the present using the following key words: "adult scoliosis surgery," "adult spine deformity surgery," "outcomes," and "complications." Exclusion criteria included follow-up shorter than 2 years and mean patient age younger than 18 years. Data on major curve (coronal scoliosis or lumbar lordosis Cobb angle as reported), major curve correction, Oswestry Disability Index (ODI) scores, Scoliosis Research Society (SRS) instrument scores, complications, and pseudarthroses were recorded. RESULTS: Forty-nine articles were obtained and included in this review; 3299 patient data points were analyzed. The mean age was 47.7 years, and the mean follow-up period was 3.6 years. The average major curve correction was 26.6 degrees (for 2188 patients); for 2129 patients, it was possible to calculate average curve reduction as a percentage (40.7%). The mean total ODI was 41.2 (for 1289 patients), and the mean postoperative reduction in ODI was 15.7 (for 911 patients). The mean SRS-30 equivalent score was 97.1 (for 1700 patients) with a mean postoperative decrease of 23.1 (for 999 patients). There were 897 reported complications for 2175 patients (41.2%) and 319 pseudarthroses for 2469 patients (12.9%). CONCLUSIONS: Surgery for adult scoliosis is associated with improvement in radiographic and clinical outcomes at a minimum 2-year follow-up. Perioperative morbidity includes an approximately 13% risk of pseudarthrosis and a greater than 40% incidence of perioperative adverse events. Incidence of perioperative complications is substantial and must be considered when deciding optimal disease management. Although the quality of published studies in this area has improved, particularly in the last few years, the current review highlights the lack of routine use of standardized outcomes measures and assessment in the adult scoliosis literature.

Endocrinological and ophthalmological consequences of an initial endonasal endoscopic approach for resection of craniopharyngiomas.

OBJECT: The expanded endoscopic approach to craniopharyngiomas has recently been described in several small case series. The authors present their experience with this technique and review the available literature. METHODS: Between September 2006 and September 2009, 14 patients underwent a purely endoscopic, endonasal approach for resection of newly diagnosed craniopharyngiomas. These procedures represent index surgeries; no patient had undergone previous tumor resection. A retrospective review of endocrinological and ophthalmological outcomes, extent of resection, and complication prevalence was completed. Additionally, a review of the English literature was performed to evaluate outcomes of similar endoscopic techniques for resection of craniopharyngiomas. RESULTS: Four patients (28.6%) underwent gross-total resection; near total resection or better was achieved in 9 patients (64.3%). All patients presented with some form of visual field or acuity deficit. Postoperatively, 12 patients (85.7%) experienced visual improvement, with 6 patients (42.9%) having complete visual recovery. One patient experienced worsening of her visual deficit. Visual acuity improved in 8 patients ((57.1%), while visual field defects improved in 11 (78.6%). The pituitary stalk was preserved in all cases. Eight (57.1%) of 14 patients experienced some form of anterior pituitary dysfunction postoperatively. Although 9 patients (64.3%) were documented to have either transient or permanent new diabetes insipidus immediately after surgery, at 1-month follow-up only 1 patient met clinical criteria. Five patients (35.7%) developed CSF leaks that were successfully treated by subsequent endoscopic revision. All CSF leaks occurred early in the series. Two patients (14.2%) were treated for presumed meningitis postoperatively. CONCLUSIONS: The endoscopic endonasal approach is a minimally invasive alternative to open transcranial approaches for select craniopharyngiomas. Similar to previous transcranial series, rates of endocrinopathy and gross-total resection were dependent upon the adherence of the tumor capsule to the hypothalamus, pituitary stalk, and associated vasculature. A review of the literature suggests that the results of the current series are similar to other published series on this topic.

Cerebral cavernous malformations as a disease of vascular permeability: from bench to bedside with caution.

Tremendous insight into the molecular and genetic pathogenesis of cerebral cavernous malformations (CCMs) has been gained over the past 2 decades. This includes the identification of 3 distinct genes involved in familial CCMs. Still, a number of unanswered questions regarding the process from gene mutation to vascular malformation remain. It is becoming more evident that the disruption of interendothelial junctions and ensuing vascular hyperpermeability play a principal role. The purpose of this review is to summarize the current understanding of CCM genes, associated proteins, and functional pathways. Promising molecular and genetic therapies targeted at identified molecular aberrations are discussed as well.

Outcomes after a purely endoscopic transsphenoidal resection of growth hormone-secreting pituitary adenomas.

OBJECT: Using strict biochemical remission criteria, the authors assessed surgical outcomes after endoscopic transsphenoidal resection of growth hormone (GH)-secreting pituitary adenomas and identified preoperative factors that significantly influence the rate of remission. METHODS: A retrospective review of a prospectively maintained database was performed. The authors reviewed cases in which an endoscopic resection of GH-secreting pituitary adenomas was performed. The cohort consisted of 26 patients who had been followed for 3-60 months (mean 24.5 months). The thresholds of an age-appropriate, normalized insulin-like growth factor-I concentration, a nadir GH level after oral glucose load of less than 1.0 µg/l, and a random GH value of less than 2.5 µg/l were required to establish biochemical cure postoperatively. RESULTS: Overall, in 57.7% of patients undergoing a purely endoscopic transsphenoidal pituitary adenectomy for acromegaly, an endocrinological cure was achieved. The mean clinical follow-up duration was 24.5 months. In patients with microadenomas (4 cases) the cure rate was 75%, whereas in patients harboring macroadenomas (22 cases) the cure rate was 54.5%. Cavernous sinus invasion (Knosp Grades 3 and 4) was associated with a significantly lower remission rate (p = 0.0068). Hardy Grade 3 and 4 tumors were also less likely to achieve biochemical cure (p = 0.013). The overall complication rate was 11.5% including 2 incidents of transient diabetes insipidus and 1 postoperative CSF leak, which were treated nonoperatively. CONCLUSIONS: A purely endoscopic transsphenoidal approach to GH-secreting pituitary adenomas leads to similar outcome for noninvasive macroadenomas compared with traditional microsurgical techniques. Furthermore, this approach may often provide maximal visualization of the tumor, the pituitary gland, and the surrounding neurovascular structures.

Defining "complications" in spine surgery: neurosurgery and orthopedic spine surgeons' survey.

STUDY DESIGN: Survey of neurosurgical and orthopedic spine surgeons. OBJECTIVE: To define the "complications of spinal surgery," we surveyed a large group of practicing spine surgeons to establish a preliminary definition of perioperative complications. SUMMARY OF BACKGROUND DATA: Although the risk of complications following spinal procedures plays an important role in determining the appropriateness of surgical intervention, there is little consensus among spine surgeons regarding the definition of complications in spine surgery. The relevance of medical complications is also not clearly defined. METHODS: We surveyed a cohort of practicing spine surgeons via email and a commercially maintained website. Surgeons were presented with various complication scenarios, and asked to assess the presence or absence of a complication, as well as complication severity, with responses limited to "major complication" and "minor complication/adverse event." RESULTS: The survey was sent to approximately 2000 practicing surgeons; complete responses were received from 229, giving a response rate of 11.4%. Orthopedic surgeons comprised the majority of respondents (73%); most surgeons reported being in practice for greater than 5 years (83%). Greater than 75% of surgeons agreed on complication presence or absence in 10 of 11 scenarios assessed (91%, P<0.05). Consensus (≥70% agreement, P<0.05) as to type of complication was found in 7 of 11 scenarios presented (64%). Events deemed major complications involved either severe medical adverse events with permanent sequela or events requiring return to the operating room. Surgeons consistently considered medical adverse events, whether or not directly related to surgery, relevant to complication assessment. CONCLUSIONS: We present a practical binary definition of complications in spine surgery based upon a survey of over 200 practicing spine surgeons. Further work is required in critically assessing spine surgery complications.

Traumatic spondyloptosis of the thoracolumbar spine.

OBJECT: Traumatic Grade V thoracolumbar spondylolisthesis, or traumatic spondyloptosis (severe translation injuries), are uncommon spinal injuries. To the best of the authors' knowledge, this article represents the first reported case series of these unique spinal lesions. METHODS: The authors undertook a retrospective review of a tertiary care regional spinal cord injury patient population treated over a 10-year period (1997-2007). They analyzed data regarding age, sex, mechanism of injury, neurological status, and treatment. RESULTS: Five patients were identified (3 men and 2 women) with ages ranging from 17 to 44 years. All patients had sustained high-energy closed spinal injuries: 3 motor vehicle accidents, 1 injured in a building collapse, and 1 hurt by a fallen steel beam. Four patients, all with sagittal-plane spondyloptosis, had a complete neurological deficit (American Spinal Injury Association [ASIA] Grade A), and 1, with coronal-plane spondyloptosis, presented with an incomplete neurological deficit (ASIA Grade C). Four patients had sustained concurrent multisystem trauma. All patients underwent surgery: an isolated posterior fusion in 2 and combined posterior-anterior fusion in 3. Only the patient with an incomplete neurological deficit (coronal-plane spondyloptosis) recovered neurological function postoperatively. CONCLUSIONS: Traumatic thoracolumbar junction spondyloptosis is rare. Surgical reconstruction and stabilization allow for early mobilization and rehabilitation. In the present series, a patient with coronal-plane spondyloptosis presented with preserved neurological function. This may be due to the result of differences in resultant neurological compression due to displacement mechanics compared with sagittally displaced injuries.

Identification of complications that have a significant effect on length of stay after spine surgery and predictive value of 90-day readmission rate.

OBJECT: Complications after spine surgery have an impact on overall outcome and health care expenditures. The increased cost of complications is due in part to associated prolonged hospital stays. The authors propose that certain complications have a greater impact on length of stay (LOS) than others and that those complications should be the focus of future targeted prevention efforts. They conducted a retrospective analysis of a prospectively maintained database to identify complications with the greatest impact on LOS as well as the predictive value of these complications with respect to 90-day readmission rates. METHODS: Data on 249 patients undergoing spine surgery at Thomas Jefferson University from May to December 2008 were collected by a study auditor. Any complications occurring within 30 days of surgery were recorded as was overall LOS for each patient. Stepwise regression analysis was performed to determine whether specific complications had a statistically significant effect on LOS. For correlation, all readmissions within 90 days were recorded and organized by complication for comparison with those complications affecting LOS. RESULTS: The mean LOS for patients without postoperative complications was 6.9 days. Patients who developed pulmonary complications had an associated increase in LOS of 11.1 days (p < 0.005). The development of a urinary tract infection (UTI) was associated with an increase in LOS of 3.4 days (p = 0.002). A new neurological deficit was associated with an increase in LOS of 8.2 days (p = 0.004). Complications requiring return to the operating room (OR) showed a trend toward an increase in LOS of 4.7 days (p = 0.09), as did deep wound infections (3.3 days, p = 0.08). The most common reason for readmission was for wound drainage (n = 21; surgical drainage was required in 10 [4.01%] of these 21 cases). The most common diagnoses for readmission, in decreasing order of incidence, were categorized as hardware malpositioning (n = 4), fever (n = 4), pulmonary (n = 2), UTI (n = 2), and neurological deficit (n = 1). Complications affecting LOS were not found to be predictive of readmission (p = 0.029). CONCLUSIONS: Postoperative complications in patients who have undergone spine surgery are not uncommon and are associated with prolonged hospital stays. In the current cohort, the occurrence of pulmonary complications, UTI, and new neurological deficit had the greatest effect on overall LOS. Further study is required to determine the causative factors affecting readmission. These specific complications may be high-yield targets for cost reduction and/or prevention efforts.

ASA grade and Charlson Comorbidity Index of spinal surgery patients: correlation with complications and societal costs.

BACKGROUND CONTEXT: The Charlson Comorbidity Index (CCI) and the American Society of Anesthesiologists (ASA) Physical Status Classification System (ASA grade) are useful for predicting morbidity and mortality for a variety of disease processes. PURPOSE: To evaluate CCI and ASA grade as predictors of complications after spinal surgery and examine the correlation between these comorbidity indices and the cost of care. STUDY DESIGN/SETTING: Prospective observational study. PATIENT SAMPLE: All patients undergoing any spine surgery at a single academic tertiary center over a 6-month period. OUTCOME MEASURES: Direct health-care costs estimated from diagnosis related group and Current Procedural Terminology (CPT) codes. METHODS: Demographic data, including all patient comorbidities, procedural data, and all complications, occurring within 30 days of the index procedure were prospectively recorded. Charlson Comorbidity Index was calculated from International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) codes and ASA grades determined from the operative record. Diagnosis related group and CPT codes were captured for each patient. Direct costs were estimated from a societal perspective using Medicare rates of reimbursement. A multivariable analysis was performed to assess the association of the CCI and ASA grade to the rate of complication and direct health-care costs. RESULTS: Two hundred twenty-six cases were analyzed. The average CCI score for the patient cohort was 0.92, and the average ASA grade was 2.65. The CCI and ASA grade were significantly correlated, with Spearman ρ of 0.458 (p<.001). Both CCI and ASA grade were associated with increasing body mass index (p<.01) and increasing patient age (p<.0001). Increasing CCI was associated with an increasing likelihood of occurrence of any complication (p=.0093) and of minor complications (p=.0032). Increasing ASA grade was significantly associated with an increasing likelihood of occurrence of a major complication (p=.0035). Increasing ASA grade showed a significant association with increasing direct costs (p=.0062). CONCLUSIONS: American Society of Anesthesiologists and CCI scores are useful comorbidity indices for the spine patient population, although neither was completely predictive of complication occurrence. A spine-specific comorbidity index, based on ICD-9-CM coding that could be easily captured from patient records, and which is predictive of patient likelihood of complications and mortality, would be beneficial in patient counseling and choice of operative intervention.

Differential gene expression in anterior and posterior annulus fibrosus.

STUDY DESIGN: Laboratory study. OBJECTIVE: To evaluate the differential gene expression of cytokines and growth factors in anterior versus posterior annulus fibrosus (AF) intervertebral disc (IVD) specimens. SUMMARY OF BACKGROUND DATA: Histological analysis has demonstrated regional differences in vascular and neural ingrowth in the IVD, and similar differences may exist for cytokine and growth factor expression in patients with degenerative disc disease (DDD). Regional expression of these cytokines may also be related to the pain experienced in DDD. METHODS: IVD tissue was obtained from patients undergoing anterior lumbar interbody fusion surgery for back pain with radiological evidence of disc degeneration. For a control group, the discs of patients undergoing anterior lumbar discectomy for degenerative scoliosis were obtained as well. The tissue was carefully removed and separated into anterior and posterior AF. After tissue processing, an antibody array was completed to determine expression levels of 42 cytokines and growth factors. RESULTS: Nine discs from 7 patients with DDD and 5 discs from 2 patients with scoliosis were analyzed. In the DDD group, there were 10 cytokines and growth factors with significantly increased expression in the posterior AF versus the anterior AF ([interleukin] IL-4, IL-5, IL-6, M-CSF, MDC, tumor necrosis factor ß, EGF, IGF-1, angiogenin, leptin). In the scoliosis group, only angiogenin and PDGF-BB demonstrated increased expression in the posterior AF. No cytokines or growth factors had increased expression in the anterior AF compared with posterior AF. CONCLUSION: The posterior AF expresses increased levels of cytokines and growth factors compared with the anterior AF in patients with DDD. This differential expression may be important for targeting treatment of painful IVDs. LEVEL OF EVIDENCE: N/A.

Expression and relationship of proinflammatory chemokine RANTES/CCL5 and cytokine IL-1ß in painful human intervertebral discs.

STUDY DESIGN: Laboratory study. OBJECTIVE: To evaluate expression of chemokine regulated and normal T cell expressed and secreted (RANTES)/C-C motif ligand 5 (CCL5) and interleukins in intervertebral discs (IVDs) specimens from patients with discogram-proven painful degeneration. SUMMARY OF BACKGROUND DATA: Discogenic back pain results in tremendous costs related to treatment and lost productivity. The relationship between inflammation, degeneration (IVD), and cytokine upregulation is well established, but other mediators of the inflammatory cascade are not well characterized. METHODS: Painful IVDs were taken from 18 patients undergoing surgery for discogenic pain with positive preoperative discogram. Painless control tissue was taken at autopsy from patients without back pain/spinal pathology or spinal levels with negative discograms resected for deformity.Quantitative real time polymerase chain reaction (qRT-PCR) was performed to evaluate RANTES, IL-1ß, IL-6, and IL-8 expression in painful and control discs. RANTES and interleukin expression were analyzed on the basis of Pfirrmann grade.Disc cells were cultured in alginate beads using 2 groups: an untreated group and a group treated with 10 ng/mL IL-1ß, 10 ng/mL TNF-α, and 1% fetal bovine serum to induce a degenerative phenotype. RESULTS: Nine painless IVD specimens and 7 painful IVD specimens were collected. RANTES expression demonstrated a 3.60-fold increase in painful discs versus painless discs, a significant difference (P = 0.049). IL-1ß expression demonstrated significantly higher expression in painful discs (P = 0.03). RANTES expression data demonstrated significant upregulation with increasing Pfirrmann grade (P = 0.045). RANTES expression correlated significantly with IL-1ß expression (ρ = 0.67, P < 0.0001). RANTES expression increased more than 200-fold in the alginate culture model in cells treated with IL-1ß/TNF-α, 1% fetal bovine serum (P < 0.001). CONCLUSION: RANTES and IL-1ß expression was significantly elevated in painful IVDs after careful selection of painless versus painful IVD tissue. RANTES expression was found to correlate significantly with expression of IL-1ß. RANTES was upregulated by IL-1ß/TNF-α/1% fetal bovine serum an in vitro treatment to induce a degenerative phenotype.

Patient comorbidity score predicting the incidence of perioperative complications: assessing the impact of comorbidities on complications in spine surgery.

OBJECT: Present attempts to control health care costs focus on reducing the incidence of complications and hospital-acquired conditions (HACs). One approach uses restriction or elimination of hospital payments for HACs. Present approaches assume that all HACs are created equal and that payment restrictions should be applied uniformly. Patient factors, and especially patient comorbidities, likely impact complication incidence. The relationship of patient comorbidities and complication incidence in spine surgery has not been prospectively reported. METHODS: The authors conducted a prospective assessment of complications in spine surgery during a 6-month period; an independent auditor and a validated definition of perioperative complications were used. Initial demographics captured relevant patient comorbidities. The authors constructed a model of relative risk assessment based on the presence of a variety of comorbidities. They examined the impact of specific comorbidities and the cumulative effect of multiple comorbidities on complication incidence. RESULTS: Two hundred forty-nine patients undergoing 259 procedures at a tertiary care facility were evaluated during the 6-month duration of the study. Eighty percent of the patients underwent fusion procedures. One hundred thirty patients (52.2%) experienced at least 1 complication, with major complications occurring in 21.4% and minor complications in 46.4% of the cohort. Major complications doubled the median duration of hospital stay, from 6 to 12 days in cervical spine patients and from 7 to 14 days in thoracolumbar spine patients. At least 1 comorbid condition was present in 86% of the patients. An increasing number of comorbidities strongly correlated with increased risk of major, minor, and any complications (p = 0.017, p < 0.0001, and p < 0.0001, respectively). Patient factors correlating with increased risk of specific complications included systemic malignancy and cardiac conditions other than hypertension. CONCLUSIONS: Comorbidities significantly increase the risk of perioperative complications. An increasing number of comorbidities in an individual patient significantly increases the risk of a perioperative adverse event. Patient factors significantly impact the relative risk of HACs and perioperative complications.

Patient comorbidities and complications after spinal surgery: a societal-based cost analysis.

STUDY DESIGN: Prospective observational study. OBJECTIVE: To determine how patient comorbidities and perioperative complications after spinal surgery affect the health care costs to society. SUMMARY OF BACKGROUND DATA: Despite efforts to reduce adverse events related to spinal surgery, complications are common and significantly increased by patient comorbidities. METHODS: Patients who underwent spinal surgery at a tertiary academic center during a 6-month period (May 2008 to December 2008) were prospectively followed. All demographic data, comorbidities, procedural information, and complications to 30-day follow-up were recorded. Diagnosis-Related Group codes and Current Procedural Terminology codes were captured for each patient. Direct costs were estimated from a societal perspective, using 2008 Medicare rates of reimbursement. A multivariable analysis was performed to assess the impact of specific patient comorbidities and complications on total health care costs. RESULTS: A total of 226 cases were analyzed. The mean cost of care for cases with complications was greater than that for cases without complications ($13,518.35 [95% confidence interval (CI), $9378.80-$17,657.90]; P < 0.0001). These results were consistent across degenerative, traumatic, and tumor/infection preoperative diagnoses. Cases with major complications were more costly than those with minor complications ($13,714.88 [CI, $6353.02-$21,076.74]; P = 0.0001). Systemic malignancy and preoperative neurological comorbidity were each associated with an increase in the cost of care ($7919 [CI, $2073-$15,225]; P = 0.006] and $5508 [CI, $814-$11,198; P = 0.02]), respectively, when compared with a baseline cost of care derived from all cases in the database. The cost of care was increased by pulmonary complications ($7233 [CI, $3982.53-$11,152.88]; P < 0.0001), instrumentation malposition ($6968 [CI, $1705.90-$14,277.16]; P = 0.0062), new neurological deficit ($4537 [CI, $863.95-$9274.30]; P = 0.013), and by wound infection ($4067 [CI, $1682.79-$6872.39]; P = 0.0004), after adjustment for covariates. CONCLUSION: Both minor and major complications were found to increase the cost of care in a prospective assessment of spine surgery complications. Specific patient comorbidities and perioperative complications are associated with significant increases in the total cost of care to society.