The Effect of Parkinson's Disease on Patients Undergoing Lumbar Spine Surgery.

STUDY DESIGN: Retrospective Database Analysis. OBJECTIVE: The purpose of this study was to assess characteristics and outcomes of patients with Parkinson's disease (PD) undergoing lumbar spine surgery for degenerative conditions. METHODS: The Nationwide Inpatient Sample was examined from 2002 to 2011. Patients were included for study based on ICD-9-CM procedural codes for lumbar spine surgery and substratified to degenerative diagnoses. Incidence and baseline patient characteristics were determined. Multivariable analysis was performed to determine independent risk factors increasing incidence of lumbar fusion revision in PD patients. RESULTS: PD patients account for 0.9% of all degenerative lumbar procedures. At baseline, PD patients are older (70.7 versus 58.9, p < 0.0001) and more likely to be male (58.6% male, p < 160.0001). Mean length of stay (LOS) was increased in PD patients undergoing lumbar fusion (5.1 days versus 4.0 days, p < 0.0001) and lumbar fusion revision (6.2 days versus 4.8 days, p < 180.0001). Costs were 7.9% (p < 0.0001) higher for lumbar fusion and 25.2% (p < 0.0001) higher for lumbar fusion revision in PD patients. Multivariable analysis indicates that osteoporosis, fluid/electrolyte disorders, blood loss anemia, and insurance status are significant independent predictors of lumbar fusion revision in patients with PD. CONCLUSION: PD patients undergoing lumbar surgery for degenerative conditions have increased LOS and costs when compared to patients without PD.

The Impact of Resident Involvement in Elective Posterior Cervical Fusion.

STUDY DESIGN: Retrospective study of prospectively collected data OBJECTIVE.: The aim of this study was to assess the impact of resident surgeon involvement on patient outcomes following posterior cervical fusion (PCF) surgery. SUMMARY OF BACKGROUND DATA: Recently, there has been a significant uptrend in the number of PCF performed in the United States. Prior studies have investigated patient outcomes after cervical arthrodesis. Despite the heightened concern for patient safety and quality improvement, the data on the safety of resident participation in PCF is sparse. METHODS: The American College of Surgeons National Surgical Quality Improvement Program (ACS NSQIP) was examined from 2005 to 2012. Current Procedural Terminology codes were used to query the database for adults (≥18 years) who underwent PCF. Multivariate logistic regression models were employed on data adjusted by propensity scores to determine whether resident involvement was an independent predictor for the outcomes of interest. RESULTS: A total of 448 cases were assessed in NSQIP. Less than half of these cases involved residents (224, 43.1%). Resident involvement was found to be a significant predictor for blood transfusions [odds ratio (OR) = 1.7, confidence interval (CI) = 1.1-2.6, P = 0.010], length of stay of more than 5 days (OR = 1.6, CI = 1.0-2.6, P = 0.040), and operative time more than 4 hours (OR = 3.6, CI = 1.7-7.4, P = 0.0007). Other independent risk factors for prolonged length of stay included age 81 years or older versus 50 years or younger (OR = 4.7, CI = 1.7-12.6, P = 0.016) and diabetes (OR = 2.3, CI = 1.3-4.1, P = 0.006). In addition, multifusion was identified as a significant risk factor for extended operative time (OR = 1.8, CI = 1.1-2.9, P = 0.023). CONCLUSION: The present study used a large, nationwide sample to assess the impact of resident involvement in PCF. Resident participation was not associated with mortality, but had a minimal association with morbidity. LEVEL OF EVIDENCE: 3.

Minimally invasive cervical spine surgery.

Degenerative disorders of the cervical spine requiring surgical intervention have become increasingly more common over the past decade. Traditionally, open surgical approaches have been the mainstay of surgical treatment. More commonly, minimally invasive techniques are being developed with the intent to decrease surgical morbidity and iatrogenic spinal instability. This study will review four minimally invasive cervical techniques that have been increasingly utilized in the treatment of degenerative cervical spine disease. A series of PubMed-National Library of Medicine searches were performed. Only articles in English journals or with published with English language translations were included. Level of evidence of the selected articles was assessed. The significant incidence of postoperative dysphagia following ACDF has led to the development and increased use of zero-profile, stand-alone anterior cervical cages. The currently available literature examining the safety and effectiveness of zero-profile interbody devices supports the use of these devices in patients undergoing single-level ACDF. A multitude of studies demonstrating the significant incidence and impact of axial neck pain following open posterior spine surgery have led to a wave of research and development of techniques aimed at minimizing posterior cervical paraspinal disruption while achieving appropriate neurological decompression and/or spinal fixation. The currently available literature supports the use of minimally invasive posterior cervical laminoforaminotomy for the treatment of single-level radiculopathy. The literature suggests that fluoroscopically-assisted percutaneous cervical lateral mass screw fixation appears to be a technically feasible, safe and minimally invasive technique. Based on the currently available literature it appears that the DTRAX® expandable cage system is an effective minimally invasive posterior cervical technique for the treatment of single-level cervical radiculopathy. Minimally invasive posterior cervical techniques continue to expand with the improvement of surgical instrumentation, microsurgical techniques and improved understanding of spinal biomechanics. While several MIS approaches already exist, there is a need for advanced and improved techniques for use in posterior cervical surgery.

Postoperative Radiculopathy Caused by a Retained Fractured Pedicle Cannulation Probe and Its Mechanism of Extraction.

BACKGROUND: Spine surgery relies heavily on technology and surgical instrumentation. Improperly used instrumentation can be detrimental to the patient. Despite multiple checkpoints to ensure that foreign bodies are not retained in surgery, numerous case reports have described retained foreign bodies; however, none of these cases involve retained instrumentation after open spine surgery. Of the retained objects, 4 were sponges and one was a Jamshidi needle fragment. Although smaller objects are more commonly the culprits, surgical instruments can break off, remain stuck, and cause clinical sequelae. CASE DESCRIPTION: This case presents a retained fractured pedicle finder as the cause of right L5 radiculopathy. To our knowledge, this report is the first to describe an instrumentation-associated postoperative radiculopathy. Because of the strength with which the object was impacted, its extraction proved difficult. CONCLUSIONS: The technique of removal using a mallet and osteotome in 4 directions to loosen its hold in the vertebral body. Attempts and eventual successful removal are described.

Absent congenital cervical pedicle nearly misdiagnosed as a facet dislocation: A case report.

BACKGROUND: Cervical spinal injury encompasses up to 1.5% of all pediatric injuries. Children, and more specifically infants, are a difficult subset of patients to obtain neurological exam in the setting of trauma, thus necessitating the use of cervical X-rays, CT scans, and MRI imaging. CASE DESCRIPTION: A healthy, 15-month-old boy had an unwitnessed fall down a flight of stairs and received a CT scan of the head and cervical spine in the emergency department due to cephalohematoma and mechanism of injury. The patient was initially diagnosed with a unilateral facet dislocation but after additional imaging and rigorous interdisciplinary discussions, the patient was correctly diagnosed with a congenitally absent left C5 pedicle. Surgical intervention was not pursued and the patient was discharged home with close follow up. CONCLUSION: In the acute trauma setting, congenital absent cervical pedicle can be difficult to differentiate from unilateral facet dislocation and may require the use of advanced imaging and close communication between the neurosurgery and radiology departments. Given the high morbidity and mortality involved in the repair of facet dislocation in a child, it is crucial to maintain high degree of clinical suspicion for absent spinal pedicle. In this case, the patient nearly underwent surgical intervention, but was ultimately able to be discharged home with no symptoms or deficits after correct diagnosis.

Accuracy of Percutaneous Pedicle Screw Placement: Does Training Level Matter?

STUDY DESIGN: In vitro human cadaveric surgical technique study. OBJECTIVE: To assess the accuracy of percutaneous pedicle screw placement in a human cadaveric model using standard fluoroscopic guidance technique, compared across varying levels of experience. SUMMARY OF BACKGROUND DATA: The current literature varies widely in the reported frequency of facet violation during placement of percutaneous pedicle screws. However, as of yet there are no studies examining the effect that training level has on accuracy of placement. MATERIALS AND METHODS: Four surgeons with differing levels of training (PGY-2, PGY-4, fellow, attending) were evaluated on their accuracy of percutaneous placement of screws in a uniform manner. Each of the 10 cadavers was instrumented from L1 to S1 bilaterally, for a total of 120 screws. Specimens were dissected to evaluate for facet and pedicle wall violations. These were then recorded and analyzed to evaluate for correlation among participating surgeons, laterality, spinal level, and cadaver body mass index. RESULTS: Of 120 screws placed, there were 35 total violations [26 superior articular facet violations (21.7%), 5 intra-articular facet joint violations (4.2%), and 4 pedicle breaches (3.3%)]. Among the trainees there was no difference in the likelihood of causing a violation (P=0.8863) but there was a difference when compared with the attending surgeon (P=0.0175). Laterality (P=0.1598), spinal level (P=0.3536), and body mass index (P=0.8547) did not correlate with the likelihood of a violation. CONCLUSIONS: Surgeons of differing training levels are able to safely and accurately place lumbar pedicle screws in a percutaneous manner, with a low likelihood of facet and pedicle wall violations.

Frailty Is Predictive of Adverse Postoperative Events in Patients Undergoing Lumbar Fusion.

STUDY DESIGN: Retrospective study of prospectively collected data. OBJECTIVE: To analyze the modified frailty index (mFI) as a predictor of adverse postoperative events following posterior lumbar fusion. METHODS: The American College of Surgeons National Surgical Quality Improvement Program (ACS NSQIP) database including all adult patients undergoing posterior lumbar interbody fusion or transforaminal lumbar interbody fusion between 2005 and 2012. Outcomes measured included mortality, postoperative complications, length of stay, reoperations, and readmissions. The previously described mFI was calculated, and univariate and multivariate logistic regression analysis were used to analyze risk factors associated with morbidity, mortality, and adverse postoperative events. This study was qualified as exempt by the Mount Sinai Hospital Institutional Review Board. RESULTS: A total of 6094 patients met inclusion criteria. The mean mFI was 0.087(0-0.545). Increasing mFI score was associated with increased complications, reoperations, prolonged length of stay (LOS), and morbidity (P < .05). As the mFI score increased from 0.27 (3/11 variables present) to ≥0.36 (4/11), the rate of any complication increased from 26.8% to 35% (P < .0001), sepsis 2.4% to 5.2% (P < .0001), wound complications 4.4% to 6.5% (P < .0001), unplanned readmissions 4.7% to 20% (P = .02), and urinary tract infection 4.1% to 10.4% (P < .0001). An mFI of ≥0.36 was an independent predictor of any complication (odds ratio [OR]= 2.2, 95% confidence interval [CI] = 1.3-3.7), sepsis (OR = 6.3, 95%, CI = 1.8-21), wound complications (OR = 2.9, 95% CI = 1.1-8.2), prolonged LOS (OR = 2.3, 95% CI = 1.4-3.7), and readmission (OR = 4.3, 95% CI = 1.5-12.7). CONCLUSION: Patients with higher mFI scores (≥ 4/11 variables) are at a significantly higher risk of major complications, readmissions, and prolonged LOS following lumbar fusion.

Thirty-Day Morbidity Associated with Pelvic Fixation in Adult Patients Undergoing Fusion for Spinal Deformity: A Propensity-Matched Analysis.

STUDY DESIGN: Retrospective study of prospectively collected data. OBJECTIVE: To determine if patients undergoing spinal deformity surgery with pelvic fixation are at an increased risk of morbidity. METHODS: The American College of Surgeons National Surgical Quality Improvement Program is a large multicenter clinical registry that prospectively collects preoperative risk factors, intraoperative variables, and 30-day postoperative morbidity and mortality outcomes from ~400 hospitals nationwide. Current Procedural Terminology codes were used to query the database between 2010 and 2014 for adults who underwent fusion for spinal deformity. Patients were separated into groups of those with and without pelvic fixation. Univariate analysis and multivariate logistic regression were used to analyze the effect of pelvic fixation on the incidence of postoperative morbidity and other surgical outcomes. RESULTS: Multivariate analysis showed that pelvic fixation was a significant predictor of overall morbidity (odds ratio [OR] = 2.3, 95% confidence interval [CI]: 1.7 to 3.1, p = 0.0002), intra- or postoperative blood transfusion (OR = 2.3, 95% CI: 1.7 to 3.1 p < 0.0001), extended operative time (OR = 4.7, 95% CI: 3.1 to 7.0 p < 0.0001), and length of stay > 5 days (OR = 2.1, 95% CI 1.5 to 2.8, p < 0.0001) in patients undergoing fusion for spinal deformity. However, fusion to the pelvis did not lead to additional risk for other complications, including wound complications (p = 0.3191). CONCLUSION: Adult patients undergoing spinal deformity surgery with pelvic fixation were not susceptible to increased morbidity beyond increased blood loss, greater operative time, and extended length of stay.

Quantitative Computed Tomography Ventriculography for Assessment and Monitoring of Hydrocephalus: A Pilot Study and Description of Method in Subarachnoid Hemorrhage.

BACKGROUND: There is no facile quantitative method for monitoring hydrocephalus (HCP). We propose quantitative computed tomography (CT) ventriculography (qCTV) as a novel computer vision tool for empirically assessing HCP in patients with subarachnoid hemorrhage (SAH). METHODS: Twenty patients with SAH who were evaluated for ventriculoperitoneal shunt (VPS) placement were selected for inclusion. Ten patients with normal head computed tomography (CTH) findings were analyzed as negative controls. CTH scans were segmented both manually and automatically (by qCTV) to generate measures of ventricular volume. RESULTS: The median manually calculated ventricular volume was 36.1 cm3 (interquartile range [IQR], 30-115 cm3), which was similar to the median qCTV measured volume of 37.5 cm3 (IQR, 32-118 cm3) (P = 0.796). Patients undergoing VPS placement demonstrated an increase in median ventricular volume on qCTV from 21 cm3 to 40 cm3 on day T-2 and to 51 cm3 by day 0, a change of 144%. This is in contrast to patients who did not require shunting, in whom median ventricular volume decreased from 16 cm3 to 14 cm3 on day T-2 and to 13 cm3 by day 0, with an average overall volume decrease 19% (P = 0.001). The average change in ventricular volume predicted which patients would require VPS placement, successfully identifying 7 of 10 patients (P = 0.004). Using an optimized cutoff of a change in ventricular volume of 2.5 cm3 identified all patients who went on to require VPS placement (10 of 10; P = 0.011). CONCLUSIONS: qCTV is a reliable means of quantifying ventricular volume and hydrocephalus. This technique offers a new tool for monitoring neurosurgical patients for hydrocephalus, and may be beneficial for use in future research studies, as well as in the routine care of patients with hydrocephalus.

Incidence, Impact, and Risk Factors for 30-Day Wound Complications Following Elective Adult Spinal Deformity Surgery.

STUDY DESIGN: Case-control study. OBJECTIVE: To determine the incidence, impact, and risk factors for wound complications within 30 days following elective adult spinal deformity surgery. METHODS: Current Procedural Terminology and International Classification of Diseases, Ninth Edition, diagnosis codes were used to query the database for adults who underwent spinal deformity surgery from 2010 to 2014. Patients were separated into groups of those with and without wound complications. Univariate analysis and multivariate logistic regression were used to analyze the influence of patient factors, operative variables, and clinical characteristics on the incidence of postoperative wound complication. This study was qualified as exempt by the Mount Sinai Hospital Institutional Review Board. RESULTS: A total of 5803 patients met the criteria for this study. Wound complications occurred in 140 patients (2.4%) and were significantly associated with other adverse outcomes, including higher rates of unplanned reoperation (P < .0001) and prolonged length of stay (P < .0001). Regardless of fusion length, wound complication rates were higher with a posterior approach (short = 2.7%; long = 3.7%) than an anterior one (short = 2.2%; long = 2.7). According to the multivariate analysis, posterior fusion (odds ratio [OR] = 1.8; P = .010), obese class II (OR = 1.7; P = .046), obese class III (OR = 2.8; P < .0001), preoperative blood transfusion (OR = 6.1; P = .021), American Society of Anesthesiologists class ≥3 (OR = 1.7; P = .009), and operative time >4 hours (OR = 1.8; P = .006) were statistically significant risk factors for wound complications. CONCLUSION: The 30-day incidence of wound complication in adult spinal deformity surgery is 2.4%. The risk factors for wound complication are multifactorial. This data should provide a step toward developing quality improvement measures aimed at reducing complications in high-risk adults.

Association Between Age and Complications in Adult Scoliosis Surgery: An Analysis of the Scoliosis Research Society Morbidity and Mortality Database.

STUDY DESIGN: Retrospective review. OBJECTIVE: To assess the relationship between age and complications, and report age-stratified complication rates for the surgical treatment of adult scoliosis. SUMMARY OF BACKGROUND DATA: Literature examining age and complication rates for adult scoliosis surgery is conflicting. The Scoliosis Research Society (SRS) morbidity and mortality (M&M) database contains a large series of adult scoliosis patients that can be utilized to investigate this relationship. METHODS: The SRS M&M database was queried from 2004 to 2007 to identify all cases of adult scoliosis. Data pertaining to patient age, complications, scoliosis, and surgery type were extracted from the database. Age-based analyses of clinical parameters were conducted using age as both a stratified categorical variable and as a continuous variable. RESULTS: In our cohort of 5470 adult scoliosis patients, the overall complication rate was 13.5% and there was a 0.3% mortality rate. Patients who experienced complications were significantly older than those without complications (55.9 ± 16.5 yrs vs. 51.2 ± 18.7 yrs, P < 0.001). When complications were stratified according to decade of age, there was also a statistically significant trend of increasing complication rates with each decade of life (P < 0.001). Dural tears were the most common complication in patients over 50 years, whereas implant-related complications were the most common in patients less than 50 years. CONCLUSION: There was a clear association between increasing age and higher rates of major short-term complications, a factor that ought to be taken into account during treatment decision making and patient counseling.

Posterior-Only Circumferential Decompression and Reconstruction in the Surgical Management of Lumbar Vertebral Osteomyelitis.

Study Design Case report. Objective The purpose of this report is to discuss the surgical management of lumbar vertebral osteomyelitis with a spinal epidural abscess (SEA) and present a single-stage, posterior-only circumferential decompression and reconstruction with instrumentation using an expandable titanium cage and without segmental nerve root sacrifice as an option in the treatment of this disease process. Methods We report a 42-year-old man who presented with 3 days of low back pain and chills who rapidly decompensated with severe sepsis following admission. Magnetic resonance imaging of his lumbosacral spine revealed intramuscular abscesses of the left paraspinal musculature and iliopsoas with SEA and L4 vertebral body involvement. The patient failed maximal medical treatment, which necessitated surgical treatment as a last resort for infectious source control. He underwent a previously undescribed procedure in the setting of SEA: a single-stage, posterior-only approach for circumferential decompression and reconstruction of the L4 vertebral body with posterior segmental instrumented fixation. Results After the surgery, the patient's condition gradually improved; however, he suffered a wound dehiscence necessitating a surgical exploration and deep wound debridement. Six months after the surgery, the patient underwent a revision surgery for adjacent-level pseudarthrosis. At 1-year follow-up, the patient was pain-free and off narcotic pain medication and had returned to full activity. Conclusion This patient is the first reported case of lumbar osteomyelitis with SEA treated surgically with a single-stage, posterior-only circumferential decompression and reconstruction with posterior instrumentation. Although this approach is more technically challenging, it presents another viable option for the treatment of lumbar vertebral osteomyelitis that may reduce the morbidity associated with an anterior approach.

Outcome Instruments in Spinal Trauma Surgery: A Bibliometric Analysis.

Study Design Literature review. Objective To identify outcomes instruments used in spinal trauma surgery over the past decade, their frequency of use, and usage trends. Methods Five top orthopedic journals were reviewed from 2004 to 2013 for clinical studies of surgical intervention in spinal trauma that reported patient-reported outcome instruments use or neurologic function scale use. Publication year, level of evidence (LOE), and outcome instruments were collected for each article and analyzed. Results A total of 58 studies were identified. Among them, 26 named outcome instruments and 7 improvised questionnaires were utilized. The visual analog scale (VAS) for pain was used most frequently (43.1%), followed by the Short Form 36 (34.5%), Frankel grade scale (25.9%), Oswestry Disability Index (20.7%) and American Spinal Injury Association Impairment Scale (15.5%). LOE 4 was most common (37.9%), and eight LOE 1 studies were identified (10.3%). Conclusions The VAS pain scale is the most common outcome instrument used in spinal trauma. The scope of this outcome instrument is limited, and it may not be sufficient for discriminating between more and less effective treatments. A wide variety of functional measures are used, reflecting the need for a disease-specific instrument that accurately measures functional limitation in spinal trauma.

A Comparative Analysis Among the SRS M&M, NIS, and KID Databases for the Adolescent Idiopathic Scoliosis.

STUDY DESIGN: Retrospective cohort analysis. OBJECTIVES: A growing number of publications have utilized the Scoliosis Research Society (SRS) Morbidity and Mortality (M&M) database, but none have compared it to other large databases. The objective of this study was to compare SRS complications with those in administrative databases. SUMMARY OF BACKGROUND DATA: The Nationwide Inpatient Sample (NIS) and Kid's Inpatient Database (KID) captured a greater number of overall complications while the SRS M&M data provided a greater incidence of spine-related complications following adolescent idiopathic scoliosis (AIS) surgery. Chi-square was used to obtain statistical significance, with p < .05 considered significant. METHODS: The SRS 2004-2007 (9,904 patients), NIS 2004-2007 (20,441 patients) and KID 2003-2006 (10,184 patients) databases were analyzed for AIS patients who underwent fusion. Comparable variables were queried in all three databases, including patient demographics, surgical variables, and complications. RESULTS: Patients undergoing AIS in the SRS database were slightly older (SRS 14.4 years vs. NIS 13.8 years, p < .0001; KID 13.9 years, p < .0001) and less likely to be male (SRS 18.5% vs. NIS 26.3%, p < .0001; KID 24.8%, p < .0001). Revision surgery (SRS 3.3% vs. NIS 2.4%, p < .0001; KID 0.9%, p < .0001) and osteotomy (SRS 8% vs. NIS 2.3%, p < .0001; KID 2.4%, p < .0001) were more commonly reported in the SRS database. The SRS database reported fewer overall complications (SRS 3.9% vs. NIS 7.3%, p < .0001; KID 6.6%, p < .0001). However, when respiratory complications (SRS 0.5% vs. NIS 3.7%, p < .0001; KID 4.4%, p < .0001) were excluded, medical complication rates were similar across databases. In contrast, SRS reported higher spine-specific complication rates. Mortality rates were similar between SRS versus NIS (p = .280) and SRS versus KID (p = .08) databases. CONCLUSIONS: There are similarities and differences between the three databases. These discrepancies are likely due to the varying data-gathering methods each organization uses to collect their morbidity data. LEVEL OF EVIDENCE: Level IV.

Annular puncture with tumor necrosis factor-alpha injection enhances painful behavior with disc degeneration in vivo.

BACKGROUND CONTEXT: Painfulintervertebral disc degeneration is extremely common and costly. Effective treatments are lacking because the nature of discogenic pain is complex with limited capacity to distinguish painful conditions from age-related changes in the spine. Hypothesized sources of discogenic pain include chronic inflammation, neurovascular ingrowth, and structural disruption. PURPOSE: This study aimed to investigate inflammation, pro-neurovascular growth factors, and structural disruption as sources of painful disc degeneration STUDY DESIGN/SETTING: This study used an in vivo study to address these hypothesized mechanisms with anterior intradiscal injections of tumor necrosis factor-alpha (TNFα), pro-neurovascular growth factors: nerve growth factor and vascular endothelial growth factor (NGF and VEGF), and saline with additional sham surgery and naïve controls. Depth of annular puncture was also evaluated for its effects on structural and painful degeneration. METHODS: Rat lumbar discs were punctured (shallow or deeper puncture) and intradiscally injected with saline, TNFα, or NGF and VEGF. Structural disc degeneration was assessed using X-ray, magnetic resonance imaging (MRI), and histology. The rat painful condition was evaluated using Von Frey hyperalgesia measurements, and substance P immunostaining in dorsal root ganglion (DRG) was performed to determine the source of pain. RESULTS: Saline injection increased painful responses with degenerative changes in disc height, MRI intensity, and morphologies of disc structure and cell. TNFα and NGF/VEGF accelerated painful behavior, and TNFα-injected animals had increased substance P in DRGs. Deeper punctures led to more severe disc degeneration. Multiple regression analysis showed that the painful behavior was correlated with disc height loss. CONCLUSIONS: We concluded that rate and severity of structural disc degeneration was associated with the amount of annular disruption and puncture depth. The painful behavior was associated with disc height loss and discal inflammatory state, whereas pro-inflammatory cytokines might play a more important role in the level of pain, which might have resulted from enhanced DRG sensitization. These in vivo painful disc degeneration models with different severities of structural changes may be useful for investigating discogenic pain mechanisms and for screening therapies, although interpretations must note the differences between all surgically induced animal models and the human condition.

Surgical Morbidity and Mortality Associated With Transoral Approach to the Cervical Spine.

STUDY DESIGN: A retrospective cohort analysis of prospectively collected data. OBJECTIVE: The aim of this study was to analyze morbidity and mortality in adult patients undergoing transoral approach using a large national database. SUMMARY OF BACKGROUND DATA: The transoral approach to the anterior skull base and atlanto-axial cervical spine provides a direct corridor to the lower clivus, C1, C2, and occasionally C3. Due to the rarity of this approach and the unfamiliar anatomy, there is potential for significant morbidity and mortality. METHODS: Adult patients undergoing transoral approach to the cervical spine from 2008 to 2012 were identified by the Current Procedural Terminology (CPT) code 22548 in the ACS NSQIP database. Cases with missing preoperative information were excluded. Univariate and multivariate analyses were performed to assess associated morbidity and mortality. RESULTS: One hundred twenty-six patients underwent cervical spine and clival surgery via the transoral approach. There were a total of 27 (21.4%) postoperative complications with three (2.4%) mortalities. On multivariate analysis, there was an increased risk of complications with operative time >4 hours [odds ratio (OR) 7.8, 95% confidence interval (95% CI) 1.8-33.1, P = 0.0054] and total length of stay >5 days (OR 7.5, 95% CI 2.4-23.4, P = 0.0006). CONCLUSION: The transoral approach carries significant risks of morbidity and mortality. Maintaining operative time <4 hours and LOS <5 days may decrease morbidity and mortality. LEVEL OF EVIDENCE: 4.

Impact of Resident Involvement on Morbidity in Adult Patients Undergoing Fusion for Spinal Deformity.

STUDY DESIGN: A retrospective study of prospectively collected data. OBJECTIVE: The aim of this study was to determine whether patients undergoing spinal deformity surgery with resident involvement are at an increased risk of morbidity. SUMMARY OF BACKGROUND DATA: Resident involvement has been investigated in other orthopedic procedures but has not been studied in adult spinal deformity surgery. METHODS: The American College of Surgeons National Surgical Quality Improvement Program (ACS NSQIP) is a large multicenter clinical registry that prospectively collects preoperative risk factors, intraoperative variables, and 30-day postoperative morbidity and mortality outcomes from about 400 hospitals nationwide. Current procedural terminology (CPT) codes were used to query the database for adults who underwent fusion for spinal deformity between 2005 and 2012. Patients were separated into propensity score matched groups of those with and without resident involvement. Univariate analysis and multivariate logistic regression were used to analyze the effect of resident involvement on the incidence of postoperative morbidity and other surgical outcomes. RESULTS: Resident involvement was an independent predictor of overall morbidity [odds ratio (OR) 2.2, P < 0.0001], wound complication (OR 2.5, P = 0.0252), intra-/postoperative transfusion (OR 2.3, P < 0.0001), and length of stay > 5 days (OR 2.0, P < 0.0001). However, resident involvement was not an independent predictor for other complications, such as mortality. CONCLUSION: Resident participation was associated with significantly longer operative times. As a result, higher rate of certain morbidity, but not mortality, was found, specifically for complications that have been previously associated with long operative duration. LEVEL OF EVIDENCE: 3.

The 100 Most Influential Articles in Cervical Spine Surgery.

Study Design Literature review. Objective To identify and analyze the top 100 cited articles in cervical spine surgery. Methods The Thomson Reuters Web of Knowledge was searched for citations of all articles relevant to cervical spine surgery. The number of citations, authorship, year of publication, journal of publication, country of publication, and institution were recorded for each article. Results The most cited article was the classic from 1991 by Vernon and Mior that described the Neck Disability Index. The second most cited was Smith's 1958 article describing the anterior cervical diskectomy and fusion procedure. The third most cited article was Hilibrand's 1999 publication evaluating the incidence, prevalence, and radiographic progression of symptomatic adjacent segment disease following anterior cervical arthrodesis. The majority of the articles originated in the United States (65), and most were published in Spine (39). Most articles were published in the 1990s (34), and the three most common topics were cervical fusion (17), surgical complications (9), and biomechanics (9), respectively. Author Abumi had four articles in the top 100 list, and authors Goffin, Panjabi, and Hadley had three each. The Department of Orthopaedic Surgery at Hokkaido University in Sapporo, Japan, had five articles in the top 100 list. Conclusion This report identifies the top 100 articles in cervical spine surgery and acknowledges those individuals who have contributed the most to the advancement of the study of the cervical spine and the body of knowledge used to guide evidence-based clinical decision making in cervical spine surgery today.

Impact of Gender on 30-Day Complications After Adult Spinal Deformity Surgery.

STUDY DESIGN: Retrospective study of prospectively collected data. OBJECTIVE: To determine if postoperative morbidity for patients undergoing spinal deformity surgery varies by sex. SUMMARY OF BACKGROUND DATA: Influence of sex has been investigated in other surgical procedures but has not yet been studied in adult spinal deformity surgery. METHODS: The American College of Surgeons National Surgical Quality Improvement Program is a large multicenter clinical registry that prospectively collects preoperative risk factors, intraoperative variables, and 30-day postoperative morbidity and mortality outcomes from about 400 hospitals nationwide. Current Procedural Terminology codes were used to query the database for adults who underwent fusion for spinal deformity. Patients were separated into groups of male and female sex. Univariate analysis and multivariate logistic regression were used to analyze the effect of sex on the incidence of postoperative morbidity and mortality. RESULTS: Female sex was found to be a predictor of any complication[odds ratio (OR): 1.4, 95% confidence interval (CI) 1.2-1.7, P < 0.0001], intra- or postoperative RBC transfusion (OR: 1.6, 95% CI 1.4-1.9, P < .0001), urinary tract infection (OR: 2.0, 95% CI 1.2-3.3, P = 0.0046), and length of stay >5 days (OR: 1.3, 95% CI 1.1-1.5, P = 0.0015). Male sex was associated with higher rate of pulmonary (2.9% vs. 2.0%, P = 0.0344) and cardiac complications (0.9% vs. 0.5%, P = 0.0497). However, male sex as an independent risk factor for pulmonary (OR: 1.4, 95% CI 1.0-2.1, P = 0.0715) and cardiac complications (OR: 1.9, 95% CI 0.9-4.0, P = 0.1076) did not reach significance. CONCLUSION: Female sex was found to increase overall morbidity, particularly for urinary tract infection, transfusion, and length of stay >5 days. Male sex was associated with greater incidence of pulmonary and cardiac complications. Thus, sex and other patient characteristics highlighted must be considered as part of surgical risk planning and patient counseling. LEVEL OF EVIDENCE: 3.

The Burden of Clostridium difficile after Cervical Spine Surgery.

Study Design Retrospective database analysis. Objective The purpose of this study is to investigate incidence, comorbidities, and impact on health care resources of Clostridium difficile infection after cervical spine surgery. Methods A total of 1,602,130 cervical spine surgeries from the Nationwide Inpatient Sample database from 2002 to 2011 were included. Patients were included for study based on International Classification of Diseases Ninth Revision, Clinical Modification procedural codes for cervical spine surgery for degenerative spine diagnoses. Baseline patient characteristics were determined. Multivariable analyses assessed factors associated with increased incidence of C. difficile and risk of mortality. Results Incidence of C. difficile infection in postoperative cervical spine surgery hospitalizations is 0.08%, significantly increased since 2002 (p < 0.0001). The odds of postoperative C. difficile infection were significantly increased in patients with comorbidities such as congestive heart failure, renal failure, and perivascular disease. Circumferential cervical fusion (odds ratio [OR] = 2.93, p < 0.0001) increased the likelihood of developing C. difficile infection after degenerative cervical spine surgery. C. difficile infection after cervical spine surgery results in extended length of stay (p < 0.0001) and increased hospital costs (p < 0.0001). Mortality rate in patients who develop C. difficile after cervical spine surgery is nearly 8% versus 0.19% otherwise (p < 0.0001). Moreover, multivariate analysis revealed C. difficile to be a significant predictor of inpatient mortality (OR = 3.99, p < 0.0001). Conclusions C. difficile increases the risk of in-hospital mortality and costs approximately $6,830,695 per year to manage in patients undergoing elective cervical spine surgery. Patients with comorbidities such as renal failure or congestive heart failure have increased probability of developing infection after surgery. Accepted antibiotic guidelines in this population must be followed to decrease the risk of developing postoperative C. difficile colitis.