John M. Caridi

Frailty Index Is a Significant Predictor of Complications and Mortality After Surgery for Adult Spinal Deformity

Study Design. Retrospective study of prospectively collected data. Objective. To determine if the modified Frailty Index (mFI) could be used to predict postoperative complications in patients undergoing surgery for adult spinal deformity (ASD). Summary of Background Data. Surgery for patients with ASD is associated with high complication rates and significant concerns present during risk stratification with older patients. The mFI is an evaluation tool to describe the frailness of an individual and how their preoperative status may impact postoperative survival and outcomes. Using a large nationwide database, we assessed the utility of this instrument in patients undergoing surgery for ASD. Methods. The American College of Surgeons National Surgical Quality Improvement Program is a large multicenter clinical registry that prospectively collects preoperative variables, patient demographics, operative factors, 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. The previously described mFI was calculated based on the number of positive factors and univariate and multivariate logistic regression analysis were used to analyze the risk factors associated with mortality. Results. Overall, 1001 patients were identified and the mean mFI score was 0.09 (range: 0–0.545). Increasing mFI score was associated with higher complication, reoperation, and mortality rates (P < 0.05). mFI of 0.09 and 0.18 was an independent predictor of any complication, mortality, requiring a blood transfusion, pulmonary embolism/deep vein thrombosis, and reoperation (all P < 0.05). In comparison with age >60 years obesity class III, mFI was a superior predictor of several postoperative complications and reoperation. Conclusion. Frailty was an independent predictor of postoperative complications, mortality, and reoperation in patients undergoing surgery for ASD. Preoperative assessment of the mFI in this patient population can be utilized to improve current risk models. Level of Evidence: 3

The Top 100 Classic Papers in Lumbar Spine Surgery

Study Design. Bibliometric review of the literature. Objective. To analyze and quantify the most frequently cited papers in lumbar spine surgery and to measure their impact on the entire lumbar spine literature. Summary of Background Data. Lumbar spine surgery is a dynamic and complex field. Basic science and clinical research remain paramount in understanding and advancing the field. While new literature is published at increasing rates, few studies make long-lasting impacts. Methods. The Thomson Reuters Web of Knowledge was searched for citations of all papers relevant to lumbar spine surgery. The number of citations, authorship, year of publication, journal of publication, country of publication, and institution were recorded for each paper. Results. The most cited paper was found to be the classic paper from 1990 by Boden et al that described magnetic resonance imaging findings in individuals without back pain, sciatica, and neurogenic claudication showing that spinal stenosis and herniated discs can be incidentally found when scanning patients. The second most cited study similarly showed that asymptomatic patients who underwent lumbar spine magnetic resonance imaging frequently had lumbar pathology. The third most cited paper was the 2000 publication of Fairbank and Pynsent reviewing the Oswestry Disability Index, the outcome-measure questionnaire most commonly used to evaluate low back pain. The majority of the papers originate in the United States (n = 58), and most were published in Spine (n = 63). Most papers were published in the 1990s (n = 49), and the 3 most common topics were low back pain, biomechanics, and disc degeneration. Conclusion. This report identifies the top 100 papers in lumbar spine surgery and acknowledges those individuals who have contributed the most to the advancement of the study of the lumbar spine and the body of knowledge used to guide evidence-based clinical decision making in lumbar spine surgery today. 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 Smiths 1958 article describing the anterior cervical diskectomy and fusion procedure. The third most cited article was Hilibrands 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.

Reoperations Following Cervical Disc Replacement

Cervical disc replacement (CDR) has emerged as an alternative surgical option to cervical arthrodesis. With increasing numbers of patients and longer follow-ups, complications related to the device and/or aging spine are growing, leaving us with a new challenge in the management and surgical revision of CDR. The purpose of this study is to review the current literature regarding reoperations following CDR and to discuss about the approaches and solutions for the current and future potential complications associated with CDR. The published rates of reoperation (mean, 1.0%; range, 0%-3.1%), revision (mean, 0.2%; range, 0%-0.5%), and removal (mean, 1.2%; range, 0%-1.9%) following CDR are low and comparable to the published rates of reoperation (mean, 1.7%; range; 0%-3.4%), revision (mean, 1.5%; range, 0%-4.7%), and removal (mean, 2.0%; range, 0%-3.4%) following cervical arthrodesis. The surgical interventions following CDR range from the repositioning to explantation followed by fusion or the reimplantation to posterior foraminotomy or fusion. Strict patient selection, careful preoperative radiographic review and surgical planning, as well as surgical technique may reduce adverse events and the need for future intervention. Minimal literature and no guidelines exist for the approaches and techniques in revision and for the removal of implants following CDR. Adherence to strict indications and precise surgical technique may reduce the number of reoperations, revisions, and removals following CDR. Long-term follow-up studies are needed, assessing the implant survivorship and its effect on the revision and removal rates.

Coagulation Profile as a Risk Factor for 30- Day Morbidity and Mortality Following Posterior Lumbar Fusion.

Study Design. A retrospective cohort study. Objective. The aim of this study was to identify associations between abnormal coagulation profile and postoperative morbidity and mortality in patients undergoing posterior lumbar fusion (PLF). Summary of Background Data. The literature suggests that abnormal coagulation profile is associated with postoperative complications, notably the need for blood transfusion. However, there is little research that directly addresses the influence of coagulation profile on postoperative complications following PLF. Methods. The American College of Surgeons National Surgical Quality Improvement Program database (ACS-NSQIP) was utilized to identify patients undergoing PLF between 2006 and 2013. Nine thousand two hundred ninety-five patients met inclusion criteria. Multivariate analysis was utilized to identify associations between abnormal coagulation profile and postoperative complications. Results. Low platelet count was an independent risk factor for organ space surgical site infections (SSIs) [odds ratio (OR) = 6.0, P < 0.001], ventilation >48 hours (OR = 4.5, P = 0.002), Acute renal failure (OR = 5.8, P = 0.007), transfusion (OR = 1.6, P < 0.001), sepsis (OR = 2.2, P = 0.037), reoperation (OR = 2.5, P = 0.001), and death (OR = 3.7, P = 0.049). High partial thromboplastin time (PTT) was an independent risk factor for ventilation >48 hours (OR = 5.6, P = 0.002), cerebrovascular accident (CVA)/stroke with neurological deficit (OR = 5.1, P = 0.011), cardiac arrest (OR = 5.4, P = 0.030), transfusion (OR = 1.5, P = 0.020), and death (OR = 4.5, P = 0.050). High International Normalized Ration (INR) was an independent risk factor for pneumonia (OR = 8.7, P = 0.001), pulmonary embolism (OR = 5.6, P = 0.021), deep venous thrombosis/Thrombophlebitis (OR = 4.8, P = 0.011), septic shock (OR = 8.4, P = 0.048), and death (OR = 9.8, P = 0.034). Bleeding disorder was an independent risk factor for organ space SSI (OR = 5.4, P = 0.01), pneumonia (OR = 3.0, P = 0.023), and sepsis (OR = 4.4, P < 0.001). Conclusion. Abnormal coagulation profile was an independent predictor of morbidity and mortality in patients undergoing PLF. As such, it should be considered in preoperative optimization and risk stratification. Level of Evidence: 3

Association Between Surgeon Experience and Complication Rates in Adult Scoliosis Surgery: A Review of 5117 Cases From the Scoliosis Research Society Database 2004-2007.

Study Design. Retrospective review of a multicenter database. Objective. To evaluate whether surgeon experience is associated with complication rates in adult spinal deformity (ASD) surgery. Summary of Background Data. Multiple patient- and surgery-related factors have been shown to increase the risk of complications in ASD. No study exists evaluating surgeon experience as an associated factor with complications in ASD. Methods. The Scoliosis Research Society Morbidity and Mortality database was queried for patients older than 18 years who underwent ASD from 2004 to 2007. Patient demographics, surgical characteristics, complications, and surgeon membership status were analyzed. Two-tailed t test and &khgr;2 tests were performed, with P value of less than 0.05 considered significant. Results. A total of 5117 patients underwent ASD surgery. The average patient age was 51.8 years. Patients operated by candidate members were older than those operated by active members (53.1 vs. 51.4, P = 0.003). Active members performed 3836 (75%) cases whereas candidate members performed 1281 cases. There were 1110 (21.7%) revisions. A total of 681 (13.3%) complications were recorded, 498 (13.0%) for active and 183 (14.3%) for candidate members, respectively (P = 0.24). Mortality rate was 0.29%. Spinal cord complications accounted for 0.68% of all cases. Active members had 21 (0.55%) spinal cord complications, whereas candidates had 14 (1.1%) (P = 0.049). There were a total of 174 (3.4%) surgical site infections (SSI). Active members had 82 (2.1%) deep SSI, whereas candidate members had 36 (2.8%) deep SSI (P = 0.164). Active members had 33 (0.9%) superficial SSI whereas candidate members had 23 (1.8%) superficial SSI (P = 0.008). Conclusion. There was a statistically significant, 2-fold increase in the rate of spinal cord complications and superficial SSI among candidate compared with active members. Overall complication rates were similar between candidate and active members. Level of Evidence: 4

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

Curvularia Abscess of the Brainstem

OBJECTIVE To present a unique case of a brainstem Curvularia fungal infection and review the diagnosis and management of this rare phenomenon. METHODS A 33-year-old immunocompetent African American male presented with 2 weeks of headache, nausea, and vomiting in a setting of a recent 20-lb weight loss. Neurological examination was positive for multiple cranial nerve palsies, hemisensory loss, and gait instability. Magnetic resonance imaging demonstrated an enhancing medullary lesion. RESULTS Metastatic and infectious workup revealed a left lung lesion, which on subsequent biopsy was positive for a granuloma yielding no further clues to the etiology of the brainstem lesion. On surgical exploration of the cranial lesion, a puss-filed, encapsulated lesion was encountered that was tightly adherent to the brainstem. Intraoperative biopsy of the lesion capsule was initially negative but on postoperative day 9, fungal hyphae were encountered identified on morphology as Curvularia species. The patient was started on triple antifungal therapy but necessitated a second surgery for lesion debulking and drainage. The patient was discharged home 10 weeks after initial presentation. At the 13-months follow-up the patient is doing very well and his neurological examination continues to improve. CONCLUSIONS This is the first reported case of a brainstem Curvularia infection. This case highlights the importance of an aggressive surgical and antibiotic therapy in the treatment of central nervous system Curvularia infections. There appears to be a strong relationship between heavy marijuana use and Curvularia infection, producing lung granulomas that may extend to other organs such as the central nervous system of immunocompetent patients.

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

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.