Faculty Bibliography

PURPOSE: The aim of this study is to report and quantify the associated factors for morbidity and mortality following surgical management of cervical spondylotic myelopathy (CSM). METHODS: The Nationwide Inpatient Sample (NIS) database was use to retrospectively review all patients over 25 years of age with a diagnosis of CSM who underwent anterior and/or posterior cervical fusion or laminoplasty between 2001 and 2010. The main outcome measures were total procedure-related complications and mortality. Multivariate regression analysis was used to identify demographic, comorbidity, and surgical parameters associated with increased morbidity and mortality risk [reported as: OR (95 % CI)]. RESULTS: A total of 54,348 patients underwent surgical intervention for CSM with an overall morbidity rate of 9.83 % and mortality rate of 0.43 %. Comorbidities found to be associated with an increased complication rate included: pulmonary circulation disorders [6.92 (5.91-8.12)], pathologic weight loss [3.42 (3.00-3.90)], and electrolyte imbalance [2.82 (2.65-3.01)]. Comorbidities found to be associated with an increased mortality rate included: congestive heart failure [4.59 (3.62-5.82)], pulmonary circulation disorders [11.29 (8.24-15.47)], and pathologic weight loss [5.43 (4.07-7.26)]. Alternatively, hypertension [0.56 (0.46-0.67)] and obesity [0.36 (0.22-0.61)] were found to confer a decreased risk of mortality. Increased morbidity and mortality rates were also identified for fusions of 4-8 levels [morbidity: 1.55 (1.48-1.62), mortality: 1.80 (1.48-2.18)] and for age >65 years [morbidity: 1.65 (1.57-1.72), mortality: 2.74 (2.25-3.34)]. An increased morbidity rate was found for posterior-only [1.55 (1.47-1.63)] and combined anterior and posterior fusions [3.20 (2.98-3.43)], and an increased mortality rate was identified for posterior-only fusions [1.87 (1.40-2.49)]. Although revision fusions were associated with an increased morbidity rate [1.81 (1.64-2.00)], they were associated with a decreased rate of mortality [0.24 (0.10-0.59)]. CONCLUSION: The NIS database was used to provide national estimates of morbidity and mortality following surgical management of CSM in the United States. Several comorbidities, as well as demographic and surgical parameters, were identified as associated factors.

STUDY DESIGN: Retrospective cohort study. OBJECTIVE: To assess the rate and causes of unplanned readmissions after surgical treatment of common degenerative lumbar pathologies within 90 days. SUMMARY OF BACKGROUND DATA: With pay-for performance and bundled payment compensation models being implemented; there is a growing emphasis to decrease the number of unplanned readmissions after surgery. Reports on degenerative lumbar spine pathology readmission rates are often obtained from national databases that lack clinical detail. Less published are the results from single-center institutions. METHODS: Hospital administrative database from a single-tertiary institution was queried to identify patients who underwent surgery for 6 common lumbar pathologies during a period from 2011 to 2013. All readmissions within 90 days of discharge were reviewed for cause and rate of unplanned readmissions was calculated. RESULTS: A total of 1306 patients were identified who underwent surgery for various lumbar pathologies during a 2-year time period. There were a total of 70 readmissions captured in the database that included 14 planned, 43 unplanned readmissions, and 13 coding errors. The unplanned readmission rate varied between 2.1% and 7.1% depending on pathology, with an overall rate of 3.3% within 90 days of discharge. Index length of stay, discharge disposition, severity of illness scores, and surgical approach were associated with readmission. The addition of fusion to decompression procedures did not seem to increase readmission rates. Surgical site infections and wound complications were the 2 most common reasons for readmissions accounting for 72% of all readmissions during the 90-day postdischarge period. CONCLUSION: The rate of readmission after surgery for common lumbar degenerative pathologies is relatively low. Surgical site infections and wound complications were the most common cause of readmission in this patient cohort. LEVEL OF EVIDENCE: 4.

BACKGROUND CONTEXT: Intraoperative neuromonitoring (IOM) of spinal cord and nerve root injury through somatosensory evoked potentials (SSEP), transcranial motor evoked potentials (TcMEP), spontaneous electromyography (sEMG), and triggered electromyography (tEMG) modalities is vital during spinal surgery. However, there are currently no practice guidelines or practice patterns for the utilization of unimodal or multimodal IOM (MIOM) for specific spinal surgeries. PURPOSE: This pilot study documents practice patterns of IOM for select spinal procedures. STUDY DESIGN/SETTING: Questionnaire survey. PATIENT SAMPLE: 22 fellowship-trained spine surgeons, both surgeons and neurosurgeons, were queried on use of IOM modality combination in various spine procedures. Surgical experience varied from three to 29 years, with an average of 14.4 years. OUTCOME MEASURES: Percentage of surgeons using IOM modality or MIOM combination was calculated for each procedure. METHODS: Spine surgeons at two hospitals were surveyed on practice patterns of use of intraoperative monitoring for three deformity procedures and 21 non-deformity procedures. RESULTS: Of the 18 (81%) responses received: 15 from orthopaedic surgeons and 3 from neurosurgeons. Deformity Surgery: For both cervical and thoracic deformity surgeries, all surgeons used at least SSEP+TcMEP. For cervical surgeries, 47% of surgeons additionally used sEMG while for thoracic 71% of surgeons additionally used sEMG+tEMG. Most surgeons (44%) used all four modalities for lumbar deformity surgery. Non-Deformity surgery: For patients having radiculopathy undergoing ACDF, SSEP alone was utilized by 29%. However, in patients undergoing ACDF with symptoms of myelopathy, most surgeons (31%) used SSEP+TcMEP with only 13% using SSEP only. Fourty-six percent of surgeons utilized SSEP+TcMEP+sEMG for cervical arthroplasty procedures. SSEP+ TcMEP+sEMG was most commonly used for posterior cervical laminoforaminotomy, posterior cervical laminectomy and posterior cervical laminect!

BACKGROUND: Postoperative venous thromboembolic events (VTEs), which include pulmonary emboli and deep venous thromboses, are potentially preventable causes of death. The aim of this study was to investigate the patient and procedure-related risk factors for the occurrence of VTEs in patients undergoing spinal fusion.METHODS: We used ICD-9-CM (International Classification of Diseases, 9th Revision, Clinical Modification) procedure codes to identify patients in the Nationwide Inpatient Sample (NIS) database for 2001 through 2010 who were treated with spinal fusion. The occurrence of a symptomatic VTE was identified with use of ICD-9-CM diagnosis codes. Patient demographics, hospital characteristics, and comorbidities in the VTE and non-VTE groups were analyzed, and independent risk factors for VTE were identified.RESULTS: A total of 710,154 spinal fusion procedures were identified in the NIS from 2001 to 2010, and 3525 (0.50%) of these patients were recorded as having 3777 VTEs, consisting of 2038 deep venous thromboses (0.29%) and 1739 pulmonary emboli (0.24%). Patients with a VTE were older on average (57.63 years compared with 52.88 years for patients without a VTE) and more often male (VTE incidence, 0.58% compared with 0.42% for female) and black (VTE incidence, 0.78% compared with 0.47% for white). Postoperative VTE occurrence was associated with a longer hospital stay (18.0 compared with 3.94 days) and higher total hospital charges ($207,253 compared with $66,823). A number of comorbidities and procedure-related factors were identified as independent risk factors for VTE.CONCLUSIONS: We present a VTE Risk Index, based on the independent risk factors identified in this study, for the VTE following spinal fusion. In conjunction with current guidelines, this risk index can be used to guide clinical decision-making regarding VTE prophylaxis in patients undergoing spinal fusion.LEVEL OF EVIDENCE: Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

BACKGROUND: Patients with cervical disc herniations resulting in radiculopathy or myelopathy from single level disease have traditionally been treated with Anterior Cervical Discectomy and Fusion (ACDF), yet Cervical Disc Arthroplasty (CDA) is a new alternative. Expert suggestion of reduced adjacent segment degeneration is a promising future result of CDA. A cost-utility analysis of these procedures with long-term follow-up has not been previously reported. METHODS: We reviewed single institution prospective data from a randomized trial comparing single-level ACDF and CDA in cervical disc disease. Both Medicare reimbursement schedules and actual hospital cost data for peri-operative care were separately reviewed and analyzed to estimate the cost of treatment of each patient. QALYs were calculated at 1 and 2 years based on NDI and SF-36 outcome scores, and incremental cost effectiveness ratio (ICER) analysis was performed to determine relative cost-effectiveness. RESULTS: Patients of both groups showed improvement in NDI and SF-36 outcome scores. Medicare reimbursement rates to the hospital were $11,747 and $10,015 for ACDF and CDA, respectively; these figures rose to $16,162 and $13,171 when including physician and anesthesiologist reimbursement. The estimated actual cost to the hospital of ACDF averaged $16,108, while CDA averaged $16,004 (p = 0.97); when including estimated physicians fees, total hospital costs came to $19,811 and $18,440, respectively. The cost/QALY analyses therefore varied widely with these discrepancies in cost values. The ICERs of ACDF vs CDA with Medicare reimbursements were $18,593 (NDI) and $19,940 (SF-36), while ICERs based on actual total hospital cost were $13,710 (NDI) and $9,140 (SF-36). CONCLUSIONS: We confirm the efficacy of ACDF and CDA in the treatment of cervical disc disease, as our results suggest similar clinical outcomes at one and two year follow-up. The ICER suggests that the non-significant added benefit via ACDF comes at a reasonable cost, whether we use actual hospital costs or Medicare reimbursement values, though the actual ICER values vary widely depending upon the CUA modality used. Long term follow-up may illustrate a different profile for CDA due to reduced cost and greater long-term utility scores. It is crucial to note that financial modeling plays an important role in how economic treatment dominance is portrayed.

BACKGROUND: Cervical laminoplasty (CLP) and posterior cervical laminectomy and fusion (CLF) are well-established surgical procedures used in the treatment of cervical spondylotic myelopathy (CSM). In situations of clinical equipoise, an influential factor in procedural decision making could be the economic effect of the chosen procedure. The object of this study is to compare and analyze the total hospital costs and charges pertaining to patients undergoing CLP or CLF for the treatment of CSM. METHODS: We performed a retrospective review of 81 consecutive patients from a single institution; 55 patients were treated with CLP and 26 with CLF. CLP was performed via the double-door allograft technique that does not require implants, whereas laminectomy fusion procedures included metallic instrumentation. We analyzed 10,682 individual costs (HC) and charges (HCh) for all patients, as obtained from hospital accounting data. The Current Procedural Terminology codes were used to estimate the physicians' fees as such fees are not accounted for via hospital billing records. Total cost (TC) therefore equaled the sum of the hospital cost and the estimated physicians' fees. RESULTS: The mean length of stay was 3.7 days for CLP and 5.9 days for CLF (P < .01). There were no significant differences between the groups with respect to age, gender, previous surgical history, and medical insurance. The TC mean was $17,734 for CLP and $37,413 for CLF (P < .01). Mean HCh for CLP was 42% of that for CLF, and therefore the mean charge for CLF was 238% of that for CLP (P < .01). Mean HC was $15,426 for CLP and $32,125 for CLF (P < .01); the main contributor was implant cost (mean $2582). CONCLUSIONS: Our study demonstrates that, in clinically similar populations, CLP results in reduced length of stay, TC, and hospital charges. In CSM cases requiring posterior decompression, we demonstrate CLP to be a less costly procedure. However, in the presence of neck pain, kyphotic deformity, or gross instability, this procedure may not be sufficient and posterior CLF may be required.

Two case reports illustrate a delayed clinical presentation of incidental durotomy following surgical posterior decompression of the lumbar spine. The clinical presentation as well as radiographic imaging studies used in diagnosing this relatively rare surgical complication are discussed. Both nonoperative as well as surgical treatment alternatives are outlined.

BACKGROUND CONTEXT: The surgical management of degenerative spondylolisthesis (DS) has evolved over the past decade. The most cost effective and clinically effective procedure continues to be debated. With an aging US population and growing restraints on a financially burdened health care system, clear understanding of national trends in the surgical management of DS needs to be better defined. PURPOSE: To investigate national trends in relation to the surgical management of DS by analyzing the NIS database. STUDY DESIGN/SETTING: Analysis of the NIS database. PATIENT SAMPLE: All patients in NIS database between 2001 and 2010 treated surgically for DS. OUTCOME MEASURES: Type of surgical procedure performed, trends in surgical procedures performed, perioperative complications, length of hospital stay (LOS), total hospital charges, and Deyo index. METHODS: The NIS database was queried for patients with DS undergoing lumbar fusions between 2001 and 2010 using corresponding ICD-9 diagnosis and procedure codes. Multivariate analyses were carried out comparing instrumented posterolateral fusion alone (group 1), posterolateral fusion with anterior lumbar interbody fusion (classic 360degree procedure) (group 2), posterolateral fusion with posterior interbody fusion (single incision 360degree procedure) (group 3), anterior instrumented interbody fusion (group 4), posterior interbody fusion with posterior instrumentation (group 5). RESULTS: The total number of surgically treated DS patients increased from 29,403 in 2001 to 58,431 in 2010 with a total of 417,002 cases between 2001 and 2010. The percentage of total cases of group 1 increased from 13.7% to 18.8%, group 2 from .09% to 2.01%, group 3 from 1.92% to 2.7 %, group 4 remained constant at a rate of 4.44%, and group 5 decreased from 79.8% to 72.1%. Notable complications were acute blood loss related anemia in 14% of group 1, 20.1 % of group 2, 17% in group 3, 9% in group 4, 15% in group 5, and device related complications occurred in 1% of group 1, 4!

BACKGROUND CONTEXT: Postoperative venous thromboembolic events (VTEs), which include pulmonary embolisms (PEs) and deep venous thrombosis (DVTs), are important potentially preventable causes of death. Evidence is lacking regarding which patients are at highest risk of developing postoperative VTEs. PURPOSE: This study aims to investigate the patient and procedure determined risk factors for VTE in patients undergoing spinal surgery. STUDY DESIGN/SETTING: Retrospective analysis of a national database. PATIENT SAMPLE: Patients undergoing spinal fusion. OUTCOME MEASURES: Occurrence of postoperative complications, length of stay, total charges, mortality. METHODS: Using the National Inpatient Sample (NIS) database from 2001 through 2010 patients undergoing spinal fusions and occurrence of symptomatic VTE were identified via corresponding ICD-9 procedure and diagnosis codes. Univariate analysis of patient and hospital demographics, comorbidities, and postoperative complications was used to compare the VTE and non-VTE groups. Independent risk factors for VTE were identified via multivariate logistic regression. RESULTS: A total of 755,082 spinal fusion procedures were identified. The NIS dataset contained 2,234 DVTs (0.30%) and 1,870 PEs (0.25%), for a total of 4,104 (0.54%) VTEs in 3,831 patients. Patients who had a VTE were on average older (58.98 years for VTE, 53.53 years for no VTE, p<.01), more often women then men (VTE incidence in women 0.60% , men 0.4%, p<.01), black (white patients .48%, black .78%, p<.01), insured with Medicare or Medicaid (.77% Medicare, .71% Medicaid, .38% private insurance, p<.01), and had a higher comorbidity burden (Charlson index 1.27 versus 0.37, p<.01). Postoperative VTE was associated with longer hospital stays (18.7 days versus 4.09). VTE increased the total hospital costs (>=207,182 versus >=68,029, p<.01). The results of logistic regression models were used to construct a VTE Risk Index comprised of 29 patient and procedure related risk factors for VTE, a score!

BACKGROUND CONTEXT: Comparative effectiveness as well as cost analysis research are gaining popularity within the field of spinal surgery. In general, prior studies have shown that surgical interventions with a cost per Quality Adjusted Life Year (QALY) less than >=100,000 are cost-effective for our society. Cost-effectiveness studies for surgical management of spondylolisthesis are lacking. PURPOSE: The purpose of this study is to determine the cost/QALYof lumbar spondylolisthesis treated with multiple surgical techniques, and to identify preoperative factors that lead to cost-effectiveness at 2-year follow-up. STUDY DESIGN/SETTING: Retrospective analysis of prospectively collected data. PATIENT SAMPLE: Patients who underwent surgery for degenerative or isthmic spondylolisthesis at a single institution from 2009-2011. OUTCOME MEASURES: Oswestry Disability Index, change in QALY, cost/QALY. METHODS: We performed a retrospective analysis of prospectively collected data on 44 patients who underwent surgery for degenerative or isthmic spondylolisthesis. There were 30 cases of degenerative and 14 cases of isthmic spondylolisthesis. There were 27 women and 17 men, with an average age at surgery of 59.7 years old (SD 14.8). The change in QALY was determined from the 2-year outcome scores using EuroQol-5D. Outcomes were also assessed using the Oswestry Disability Index (ODI). Hospital DRG codes were used to assess Medicare based hospital costs. Surgical, neuromonitoring, and anesthesia CPT codes were used to determine additional direct care costs of surgery. Analysis was performed to determine which factors were associated with a cost/QALY less than >=100,000, thereby making the procedure cost-effective. Statistical analysis was performed using ANOVA, Chi Square, and linear regression analysis. RESULTS: The average length of follow up was 2 years (SD 0.82). The average postoperative improvement in ODI was 24.5 (SD 23.9) and change in QALYwas 0.4449 (SD 0.2984). The average cost/QALYat 2-year follow-up !