Hamid Hassanzadeh

Clinical Results and Functional Outcomes of Primary and Revision Spinal Deformity Surgery in Adults

BACKGROUND Few studies have examined the postsurgical functional outcomes of adults with spinal deformities, and even fewer have focused on the functional results and complications among older adults who have undergone primary or revision surgery for spinal deformity. Our goal was to compare patient characteristics, surgical characteristics, duration of hospitalization, radiographic results, complications, and functional outcomes between adults forty years of age or older who had undergone primary surgery for spinal deformity and those who had undergone revision surgery for spinal deformity. METHODS We retrospectively reviewed the cases of 167 consecutive patients forty years of age or older who had undergone surgery for spinal deformity performed by the senior author (K.M.K.) from January 2005 through June 2009 and who were followed for a minimum of two years. We divided the patients into two groups: primary surgery (fifty-nine patients) and revision surgery (108 patients). We compared the patient characteristics (number of levels arthrodesed, type of procedure, estimated blood loss, and total operative time), duration of hospitalization, radiographic results (preoperative, six-week postoperative, and most recent follow-up Cobb angle measurements for thoracic and lumbar curves, thoracic kyphosis, and lumbar lordosis), major and minor complications, and functional outcome scores (Scoliosis Research Society-22 Patient Questionnaire and Oswestry Disability Index). RESULTS The groups were comparable with regard to most parameters. However, the revision group had more patients with sagittal plane imbalance and more frequently required pedicle subtraction osteotomies (p < 0.01). Patients in the primary group required more correction in the coronal plane than did patients in the revision group, whereas patients in the revision group required more correction in the sagittal plane. We found no significant difference between the two groups in the rate of major complications or in the Scoliosis Research Society-22 Patient Questionnaire functional outcome scores. There were significant improvements in many functional outcome scores in both groups between the preoperative and early (six-week) postoperative periods and between the early postoperative period and the time of final follow-up. CONCLUSIONS Revision surgery for spinal deformity in adults, although technically challenging and considered to present a higher risk than primary surgery, was shown to have a complication rate and outcomes that were comparable with those of primary spinal deformity surgery in adults. LEVEL OF EVIDENCE Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Pelvic Fixation in Adult and Pediatric Spine Surgery: Historical Perspective, Indications, and Techniques: AAOS Exhibit Selection.

Achieving solid osseous fusion across the lumbosacral junction has historically been, and continues to be, a challenge in spine surgery. Robust pelvic fixation plays an integral role in achieving this goal. The goals of this review are to describe the history of and indications for spinopelvic fixation, examine conventional spinopelvic fixation techniques, and review the newer S2-alar-iliac technique and its outcomes in adult and pediatric patients with spinal deformity. Since the introduction of Harrington rods in the 1960s, spinal instrumentation has evolved substantially. Indications for spinopelvic fixation as a means to achieve lumbosacral arthrodesis include a long arthrodesis (five or more vertebral levels) or use of three-column osteotomies in the lower thoracic or lumbar spine, surgical treatment of high-grade spondylolisthesis, and correction of lumbar deformity and pelvic obliquity. A variety of techniques have been described over the years, including Galveston iliac rods, Jackson intrasacral rods, the Kostuik transiliac bar, iliac screws, and S2-alar-iliac screws. Modern iliac screws and S2-alar-iliac screws are associated with relatively low rates of pseudarthrosis. S2-alar-iliac screws have the advantages of less implant prominence and inline placement with proximal spinal anchors. Collectively, these techniques provide powerful methods for obtaining control of the pelvis in facilitating lumbosacral arthrodesis.

Sentinel events in cervical spine surgery.

Study Design. Retrospective cohort. Objective. A national population-based database was queried to investigate the incidence of sentinel events in cervical spine surgery as well as the associated perioperative outcomes. Summary of Background Data. Sentinel events in cervical spine surgery are potentially catastrophic complications. The incidence and perioperative outcomes associated with sentinel events in cervical spine surgery have not been well characterized. Methods. The Nationwide Inpatient Sample was queried from 2002 to 2011. Patients who underwent elective cervical spinal surgery were identified. Sentinel events including esophageal perforation, vascular injury, nerve injury, retention of foreign objects, and wrong-site surgery were identified. Patient demographics, comorbidities (Charlson Comorbidity Index), surgical procedures, length of stay, total hospital costs, and postoperative outcomes were assessed. The risk for in-hospital mortality associated with each complication was calculated using a 95% confidence interval (CI). Statistical analysis was performed with SPSS version 20, and a P ⩽ 0.001 denoted significance. Results. A total of 251,318 cervical spine procedures were identified between 2002 and 2011, of which 123 patients (0.5 per 1000 cases) incurred sentinel events. Circumferential cervical fusion (anterior-posterior cervical fusion) demonstrated an increased risk of vascular injury (odds ratio [OR], 4.5; CI, 1.8–11.2), whereas cervical total disc replacement was associated with an increased risk of esophageal perforation (OR, 10.9; CI, 1.4–85.2) and nerve injury (OR, 36.4; CI, 1.5–892.3). Posterior cervical fusions were associated with an increased risk of wrong-site surgery (OR, 3.9; CI, 1.5–10.5). The sentinel event cohort incurred longer hospitalization, greater costs, mortality, and greater incidence of postoperative complications. Conclusion. This database analysis demonstrates that sentinel events are associated with a significant increase in hospital resource utilization and worsened perioperative outcomes. The type of cervical spine procedure and the number of fusion levels significantly impact the risk of sentinel events. Further research is warranted to understand the etiology of sentinel events in cervical spine surgery and to implement protocols to mitigate the associated risk factors. Level of Evidence: 4

Incidence, risk factors, and outcomes of postoperative airway management after cervical spine surgery.

Study Design. Retrospective database analysis. Objective. To identify the incidence and risk factors for a prolonged intubation or an unplanned reintubation after cervical spine surgery (CSS). Summary of Background Data. Patients who undergo CSS occasionally require prolonged mechanical ventilation or an unplanned reintubation for airway support. Despite the potential severity of these complications, there are limited data in the published literature addressing this issue. Methods. The American College of Surgeons National Surgical Quality Improvement Program database was queried to identify patients who underwent a CSS. Patients who required a prolonged intubation more than 48 hours or an unplanned reintubation after CSS were compared with those without airway compromise. Preoperative patient characteristics, intraoperative variables, hospital length of stay, 30-day complication rates, and mortality were compared between the cohorts. An &agr; ⩽ 0.001 denoted statistical significance. A multivariate regression model was used to identify independent predictors for a prolonged intubation and an unplanned reintubation. Results. A total of 8648 cervical spine procedures were identified from 2006 to 2011 of which 54 patients (0.62%) required prolonged ventilation and 56 patients (0.64%) underwent a postoperative reintubation. Patients who required postoperative airway management were older and demonstrated a greater comorbidity burden (P < 0.001). In addition, the affected cohorts demonstrated a significantly greater rate of readmissions, reoperations, postoperative complications, and mortality (P < 0.001). Regression analysis identified the independent predictors for prolonged ventilation to include a history of cardiac disease and dialysis along with a low preoperative albumin level (P < 0.05). Similarly, the independent risk factors for a postoperative reintubation included a history of recent weight loss more than 10%, recent operation within 30 days, low preoperative hematocrit, and a high serum creatinine (P < 0.05). Conclusion. Postoperative airway management is a rare complication after CSS. A prolonged intubation and an unplanned reintubation carry a greater rate of postoperative complications and mortality. High-risk patients should be identified prior to surgery to mitigate the risk factors for postoperative airway compromise. Level of Evidence: 3

Complications after lumbar spine surgery between teaching and nonteaching hospitals.

Study Design. Retrospective national database analysis. Objective. A national population-based database was analyzed to characterize the perioperative complications of lumbar spine procedures performed at teaching and nonteaching hospitals. Summary of Background Data. Perception biases exist regarding the complications of lumbar spine surgery based upon the hospital teaching environment. Methods. Data from the Nationwide Inpatient Sample was queried from 2002–2011. Patients undergoing an anterior lumbar interbody fusion, posterior lumbar interbody fusion, anterior/posterior lumbar fusion, or lumbar decompression to treat lumbar degenerative pathology were identified and separated into cohorts based upon the teaching status of the hospital. Patient demographics, Charlson Comorbidity Index, length of stay, complications, mortality, and costs were assessed. Results. A total of 658,616 lumbar procedures were identified from 2002–2011, of which 367,875 (55.9%) were performed at teaching hospitals. An older patient population comprised the teaching hospital cohort and demonstrated a greater comorbidity burden than the nonteaching group (Charlson Comorbidity Index 2.90 vs. 2.55; P < 0.001). In addition, the teaching hospital cohort was associated with a significantly greater number of multilevel fusion cases (P < 0.001) and incurred a greater mean length of stay (3.7 vs. 3.0 d; P < 0.001). Patients treated at teaching hospitals demonstrated a significantly greater incidence of postoperative pulmonary embolism, deep vein thrombosis, infection, and neurological complications than the nonteaching cohort (P < 0.001). Overall, there were no significant differences in the mean total hospital costs or mortality between the hospital cohorts. Regression analysis demonstrated that teaching status was not a significant predictor of mortality (OR, 1.02; confidence interval 0.8–1.2; P = 0.8). Conclusion. Patients treated in teaching hospitals for lumbar spine surgery incurred a longer hospitalization and a greater incidence of postoperative complications including pulmonary embolism, deep vein thrombosis, infection, and neurological events. These findings may be explained by an increased complexity of procedures performed at teaching hospitals along with an older and a more comorbid patient population. Despite these differences, the teaching status was not a significant predictor of in-hospital mortality after a lumbar spine surgery. Level of Evidence: 3

Morbid Obesity and Lumbar Fusion in Patients Older Than 65 Years: Complications, Readmissions, Costs, and Length of Stay

Study Design. Retrospective database review. Objective. The aim of this study was to determine how both morbid obesity (body mass index [BMI] ≥40) and obesity (BMI 30–39.9) modify 90-day complication rates and 30-day readmission rates following 1- to 2-level, primary, lumbar spinal fusion surgery for degenerative pathology in an elderly population. Summary of Background Data. In the United States, both obese and elderly patients are known to have increased risk of complication, yet both demographics are increasingly undergoing elective lumbar spine surgery. Methods. Medicare data from 2005 to 2012 were queried for patients who underwent primary 1- to 2-level posterolateral lumbar fusion for degenerative pathology. Elderly patients undergoing elective surgery were selected and separated into three cohorts: morbidly obese (BMI ≥40; n = 2594), obese (BMI ≥30, < 40] (n = 5534), and nonobese controls (n = 48,210). Each pathologic cohort was matched to a unique subcohort from the control population. Ninety-day medical and surgical complication rates, 30-day readmission rates, length of stay (LOS), and hospital costs were then compared. Results. Both morbidly obese and obese patients had significantly higher odds of experiencing any one major medical complication (odds ratio [OR] 1.79; P < 0.0001 and OR 1.32; P < 0.0001, respectively). Wound infection (OR 3.71; P < 0.0001 and OR 2.22; P < 0.0001) and dehiscence (OR 3.80; P < 0.0001 and OR 2.59; P < 0.0001) rates were increased in morbidly obese and obese patients, respectively. Thirty-day readmissions, length of stay, and in-hospital costs were increased, with patients with morbid obesity incurring charges almost

Preoperative epidural injections are associated with increased risk of infection after single-level lumbar decompression.

8000 greater than controls. Conclusion. Patients with both obesity and morbid obesity are at significantly increased risk of major medical complications, wound complications, and 30-day readmissions. Additionally, both groups of patients have significantly increased LOS and hospital costs. Both obese and morbidly obese patients should be appropriately counseled of these risks and must be carefully selected to reduce postoperative morbidity. Level of Evidence: 3

Dislocation of a primary total hip arthroplasty is more common in patients with a lumbar spinal fusion

BACKGROUND CONTEXT Lumbar epidural steroid injections (LESIs) are often performed as a treatment option for lumbar stenosis and radiculopathy before lumbar decompression surgery. Several case series have reported spinal infections after LESIs. There is lack of literature on the rate of postoperative infections after lumbar decompression in patients who had prior LESIs. PURPOSE The goal of the present study is to employ a large national database to determine if there is an association between preoperative LESIs at various time intervals before lumbar decompression and the incidence of postoperative infection. STUDY DESIGN/SETTING Retrospective case control database study, Level III was used in this study. PATIENT SAMPLE This study comprised Medicare patients over age 65 years who had a LESI within 1 year of single-level lumbar decompression surgery. OUTCOME MEASURES International Classification of Diseases, 9th Revision diagnosis codes for postoperative infection and Current Procedural Terminology procedure codes for treatment of postoperative infection were the outcome measures for this study. METHODS The PearlDiver Patient Records Database, an insurance-based database of patient records, was used for this study. The database was queried for LESI and single-level lumbar decompression procedures using Current Procedural Terminology codes. These study patients were then divided into four separate cohorts: (1) lumbar decompression within 1 month following LESI, (2) lumbar decompression between 1 and 3 months following LESI, (3) lumbar decompression between 3 and 6 months following LESI, and (4) lumbar decompression between 6 and 12 months following LESI. Unique control groups for each study cohort were created with patients who underwent single-level lumbar decompression without previous LESI and matched for major risk factors for infection, including age, gender, smoking status, diabetes, and obesity. RESULTS Overall, the rate of postoperative infection after single-level lumbar decompression after LESI remained relatively low, ranging between 0.8% and 1.7%. The incidence of 90-day postoperative infection after lumbar decompression was significantly higher than matched controls in groups with LESI within 1 month (OR=3.2, p<.0001) and 1-3 months before surgery (OR=1.8, p<.0001). The incidence of 90-day postoperative infection was not significantly different from matched controls in groups with LESI between 3-6 months (OR=1.3, p=.15) and 6-12 months before decompression surgery (OR=1.3, p=.18) CONCLUSIONS: Single-level lumbar decompression within 3 months after LESI may be associated with an increased rate of postoperative infection. Increasing the time interval between LESI and single-level lumbar decompression surgery to at least 3 months may decrease postoperative infection rates.

Complications and Mortality after Lumbar Spinal Fusion in Elderly Patients with Late Stage Renal Disease.

Aims Lumbar fusion is known to reduce the variation in pelvic tilt between standing and sitting. A flexible lumbo‐pelvic unit increases the stability of total hip arthroplasty (THA) when seated by increasing anterior clearance and acetabular anteversion, thereby preventing impingement of the prosthesis. Lumbar fusion may eliminate this protective pelvic movement. The effect of lumbar fusion on the stability of total hip arthroplasty has not previously been investigated. Patients and Methods The Medicare database was searched for patients who had undergone THA and spinal fusion between 2005 and 2012. PearlDiver software was used to query the database by the International Classification of Diseases, 9th Revision, Clinical Modification (ICD‐9‐CM) procedural code for primary THA and lumbar spinal fusion. Patients who had undergone both lumbar fusion and THA were then divided into three groups: 1 to 2 levels, 3 to 7 levels and 8+ levels of fusion. The rate of dislocation in each group was established using ICD‐9‐CM codes. Patients who underwent THA without spinal fusion were used as a control group. Statistical significant difference between groups was tested using the chi‐squared test, and significance set at p < 0.05. Results At one‐year follow‐up, 14 747 patients were found to have had a THA after lumbar spinal fusion (12 079 1 to 2 levels, 2594 3 to 7 levels, 74 8+ levels). The control group consisted of 839 004 patients. The dislocation rate in the control group was 1.55%. A higher rate of dislocation was found in patients with a spinal fusion of 1 to 2 levels (2.96%, p < 0.0001) and 3 to 7 levels (4.12%, p < 0.0001). Patients with 3 to 7 levels of fusion had a higher rate of dislocation than patients with 1 to 2 levels of fusion (odds ratio (OR) = 1.60, p < 0.0001). When groups were matched for age and gender to the unfused cohort, patients with 1 to 2 levels of fusion had an OR of 1.93 (95% confidence interval (CI) 1.42 to 2.32, p < 0.001), and those with 3 to 7 levels of fusion an OR of 2.77 (CI 2.04 to 4.80, p < 0.001) for dislocation. Conclusion Patients with a previous history of lumbar spinal fusion have a significantly higher rate of dislocation of their THA than age‐ and gender‐matched patients without a lumbar spinal fusion.

Risk factors for revision surgery following primary adult spinal deformity surgery in patients 65 years and older.

Study Design. Retrospective database review. Objective. To assess complication and mortality rates after lumbar spinal fusion surgery in patients with late stage renal disease. Summary of Background Data. Lumbar spinal fusion surgeries are common in elderly patients who are well-known to have increased comorbidity burden. Elderly patients with severe chronic kidney disease (CKD) represent a population with poorly understood mortality and complication rates after spine surgery. Methods. Medicare data from the PearlDiver Database (2005–2012) was queried for patients who underwent primary 1–2 level posterolateral lumbar spine fusion surgeries. This cohort was divided into two study groups: a cohort with a preexisting diagnosis of late stage renal disease (N = 1654) and a control cohort of all other patients (N = 242,085). The control group was matched to the renal disease cohort by age, sex, and comorbidities. Moreover, 90-day complication rates and 90-day and 1-year mortality were assessed. Results. The renal disease cohort had increased rates of all medical complications (21.3 vs. 14.2%; odds ratio, OR, 1.64; 95% confidence intervals, CI, 1.44 –1.85; P < 0.0001). Increased rates of infection (4.4 vs. 1.8%; OR 2.43; 95% CI 1.87 – 3.16; P < 0.0001) and procedure-day blood transfusions (20.7 vs. 14.7%; OR 1.51; 95% CI 1.33 – 1.72; P < 0.0001) were also observed in the renal disease cohort. Both 90-day (1.1 vs. 0.2%; OR 5.05; 95% CI 2.90–8.77; P < 0.0001) and 1-year mortality (1.9 vs. 0.7%; OR 2.77; 95% CI 1.87–4.11; P < 0.0001) were significantly higher in the renal disease group compared with the control group. Conclusion. Elderly patients with late-stage renal disease treated with 1–2 level posterolateral lumbar fusion have 1.6 times increased odds of experiencing a major medical complication within 3 months of surgery and 2.8 times increased odds of 1-year mortality when compared with matched controls. Level of Evidence: 3