Presented at the 2012 Spine Section Meeting
Beejal Y. Amin, Tsung-Hsi Tu, William W. Schairer, Lumine Na, Steven Takemoto, Sigurd Berven, Vedat Deviren, Christopher Ames, Dean Chou, and Praveen V. Mummaneni
Administrative databases are increasingly being used to establish benchmarks for quality of care and to compare performance across peer hospitals. As proposals for accountable care organizations are being developed, readmission rates will be increasingly scrutinized. The purpose of the present study was to assess whether the all-cause readmissions rate appropriately reflects the University of California, San Francisco (UCSF) Medical Center hospital's clinically relevant readmission rate for spine surgery patients and to identify predictors of readmission.
Data for 5780 consecutive patient encounters managed by 10 spine surgeons at UCSF Medical Center from October 2007 to June 2011 were abstracted from the University HealthSystem Consortium (UHC) using the Clinical Data Base/Resource Manager. Of these 5780 patient encounters, 281 patients (4.9%) were rehospitalized within 30 days of the previous discharge date. The authors performed an independent chart review to determine clinically relevant reasons for readmission and extracted hospital administrative data to calculate direct costs. Univariate logistic regression analysis was used to evaluate possible predictors of readmission. The two-sample t-test was used to examine the difference in direct cost between readmission and nonreadmission cases.
The main reasons for readmission were infection (39.8%), nonoperative management (13.4%), and planned staged surgery (12.4%). The current all-cause readmission algorithm resulted in an artificially high readmission rate from the clinician's point of view. Based on the authors' manual chart review, 69 cases (25% of the 281 total readmissions) should be excluded because 39 cases (13.9%) were planned staged procedures; 16 cases (5.7%) were unrelated to spine surgery; and 14 surgical cases (5.0%) were cancelled or rescheduled at index admission due to unpredictable reasons. When these 69 cases are excluded, the direct cost of readmission is reduced by 29%. The cost variance is in excess of $3 million. Predictors of readmission were admission status (p < 0.0001), length of stay (p = 0.0001), risk of death (p < 0.0001), and age (p = 0.021).
The authors' findings identify the potential pitfalls in the calculation of readmission rates from administrative data sets. Benchmarking algorithms for defining hospitals' readmission rates must take into account planned staged surgery and eliminate unrelated reasons for readmission. When this is implemented in the calculation method, the readmission rate will be more accurate. Current tools overestimate the clinically relevant readmission rate and cost.
Abstracts of the 2013 Annual Meeting of the AANS/CNS Section on Disorders of the Spine and Peripheral Nerves
Phoenix, Arizona • March 6–9, 2013
Rajiv Saigal, Darryl Lau, Rishi Wadhwa, Hai Le, Morsi Khashan, Sigurd Berven, Dean Chou, and Praveen V. Mummaneni
Long-segment spinal instrumentation ending at the sacrum places substantial biomechanical stress on sacral screws. Iliac (pelvic) screws relieve some of this stress by supplementing the caudal fixation. It remains an open question whether there is any clinically significant difference in sacropelvic fixation with bilateral versus unilateral iliac screws. The primary purpose of this study was to compare clinical and radiographic complications in the use of bilateral versus unilateral iliac screw fixation.
The authors retrospectively reviewed 102 consecutive spinal fixation cases that extended to the pelvis at a single institution (University of California, San Francisco) in the period from 2005 to 2012 performed by the senior authors. Charts were reviewed for the following complications: reoperation, L5–S1 pseudarthrosis, sacral insufficiency fracture, hardware prominence, iliac screw loosening, and infection. The t-test, Pearson chi-square test, and Fisher exact test were used to determine statistical significance.
The mean follow-up was 31 months. Thirty cases were excluded: 12 for inadequate follow-up, 15 for lack of L5–S1 interbody fusion, and 3 for preoperative osteomyelitis. The mean age among the 72 remaining cases was 62 years (range 39–79 years). Forty-six patients underwent unilateral and 26 bilateral iliac screw fixation. Forty-one percent (n = 19) of the unilateral cases and 50% (n = 13) of the bilateral cases were treated with reoperation (p = 0.48). In addition, 13% (n = 6) of the unilateral and 19% (n = 5) of the bilateral cases developed L5–S1 pseudarthrosis (p = 0.51). There were no sacral insufficiency fractures. Thirteen percent (n = 6) of the unilateral and 7.7% (n = 2) of the bilateral cases developed postoperative infection (p = 0.70).
In a retrospective single-institution study, single versus dual pelvic screws led to comparable rates of reoperation, iliac screw removal, postoperative infection, pseudarthrosis, and sacral insufficiency fractures. For spinopelvic fixation, placing bilateral (vs unilateral) pelvic screws produced no added clinical benefit in most cases.
Darryl Lau, Andrew K. Chan, Alexander A. Theologis, Dean Chou, Praveen V. Mummaneni, Shane Burch, Sigurd Berven, Vedat Deviren, and Christopher Ames
Because the surgical strategies for primary and metastatic spinal tumors are different, the respective associated costs and morbidities associated with those treatments likely vary. This study compares the direct costs and 90-day readmission rates between the resection of extradural metastatic and primary spinal tumors. The factors associated with cost and readmission are identified.
Adults (age 18 years or older) who underwent the resection of spinal tumors between 2008 and 2013 were included in the study. Patients with intradural tumors were excluded. The direct costs of index hospitalization and 90-day readmission hospitalization were evaluated. The direct costs were compared between patients who were treated surgically for primary and metastatic spinal tumors. The independent factors associated with costs and readmissions were identified using multivariate analysis.
A total of 181 patients with spinal tumors were included (63 primary and 118 metastatic tumors). Overall, the mean index hospital admission cost for the surgical management of spinal tumors was $52,083. There was no significant difference in the cost of hospitalization between primary ($55,801) and metastatic ($50,098) tumors (p = 0.426). The independent factors associated with higher cost were male sex (p = 0.032), preoperative inability to ambulate (p = 0.002), having more than 3 comorbidities (p = 0.037), undergoing corpectomy (p = 0.021), instrumentation greater than 7 levels (p < 0.001), combined anterior-posterior approach (p < 0.001), presence of a perioperative complication (p < 0.001), and longer hospital stay (p < 0.001). The perioperative complication rate was 21.0%. Of this cohort, 11.6% of patients were readmitted within 90 days, and the mean hospitalization cost of that readmission was $20,078. Readmission rates after surgical treatment for primary and metastatic tumors were similar (11.1% vs 11.9%, respectively) (p = 0.880). Prior hospital stay greater than 15 days (OR 6.62, p = 0.016) and diagnosis of lung metastasis (OR 52.99, p = 0.007) were independent predictors of readmission.
Primary and metastatic spinal tumors are comparable with regard to the direct costs of the index surgical hospitalization and readmission rate within 90 days. The factors independently associated with costs are related to preoperative health status, type and complexity of surgery, and postoperative course.
Junseok Bae, Alexander A. Theologis, Russell Strom, Bobby Tay, Shane Burch, Sigurd Berven, Praveen V. Mummaneni, Dean Chou, Christopher P. Ames, and Vedat Deviren
Surgical treatment of adult spinal deformity (ASD) is an effective endeavor that can be accomplished using a variety of surgical strategies. Here, the authors assess and compare radiographic data, complications, and health-related quality-of-life (HRQoL) outcome scores among patients with ASD who underwent a posterior spinal fixation (PSF)–only approach, a posterior approach combined with lateral lumbar interbody fusion (LLIF+PSF), or a posterior approach combined with anterior lumbar interbody fusion (ALIF+PSF).
The medical records of consecutive adults who underwent thoracolumbar fusion for ASD between 2003 and 2013 at a single institution were reviewed. Included were patients who underwent instrumentation from the pelvis to L-1 or above, had a sagittal vertical axis (SVA) of < 10 cm, and underwent a minimum of 2 years’ follow-up. Those who underwent a 3-column osteotomy were excluded. Three groups of patients were compared on the basis of the procedure performed, LLIF+PSF, ALIF+PSF, and PSF only. Perioperative spinal deformity parameters, complications, and HRQoL outcome scores (Oswestry Disability Index [ODI], Scoliosis Research Society 22-question Questionnaire [SRS-22], 36-Item Short Form Health Survey [SF-36], visual analog scale [VAS] for back/leg pain) from each group were assessed and compared with each other using ANOVA. The minimal clinically important differences used were −1.2 (VAS back pain), −1.6 (VAS leg pain), −15 (ODI), 0.587/0.375/0.8/0.42 (SRS-22 pain/function/self-image/mental health), and 5.2 (SF-36, physical component summary).
A total of 221 patients (58 LLIF, 91 ALIF, 72 PSF only) met the inclusion criteria. Average deformities consisted of a SVA of < 10 cm, a pelvic incidence–lumbar lordosis (LL) mismatch of > 10°, a pelvic tilt of > 20°, a lumbar Cobb angle of > 20°, and a thoracic Cobb angle of > 15°. Preoperative SVA, LL, pelvic incidence–LL mismatch, and lumbar and thoracic Cobb angles were similar among the groups. Patients in the PSF-only group had more comorbidities, those in the ALIF+PSF group were, on average, younger and had a lower body mass index than those in the LLIF+PSF group, and patients in the LLIF+PSF group had a significantly higher mean number of interbody fusion levels than those in the ALIF+PSF and PSF-only groups. At final follow-up, all radiographic parameters and the mean numbers of complications were similar among the groups. Patients in the LLIF+PSF group had proximal junctional kyphosis that required revision surgery significantly less often and fewer proximal junctional fractures and vertebral slips. All preoperative HRQoL scores were similar among the groups. After surgery, the LLIF+PSF group had a significantly lower ODI score, higher SRS-22 self-image/total scores, and greater achievement of the minimal clinically important difference for the SRS-22 pain score.
Satisfactory radiographic outcomes can be achieved similarly and adequately with these 3 surgical approaches for patients with ASD with mild to moderate sagittal deformity. Compared with patients treated with an ALIF+PSF or PSF-only surgical strategy, patients who underwent LLIF+PSF had lower rates of proximal junctional kyphosis and mechanical failure at the upper instrumented vertebra and less back pain, less disability, and better SRS-22 scores.