Zoe B. Cheung

Attenuation of Proximal Junctional Kyphosis Using Sublaminar Polyester Tension Bands: A Biomechanical Study

OBJECTIVEnTo investigate the effect of sublaminar polyester tension bands on the biomechanics of the motion segments proximal to a long fusion construct.nnnMETHODSnThis was a human cadaveric biomechanical study. Pure moments of 4 Nm and 8 Nm were applied to the native spine and the instrumented spine, respectively (nxa0=xa08). The test conditions included native spine (T7-L2), fused (T10-L2), fusedxa0+ bilateral tethers tensioned to 250 N at T9-T10 (tethers 250 N), fusedxa0+ tethers tensioned to 350 N (tethers 350 N), fused (T11-L2)xa0+ tethers tensioned to 250 N at T9-T10 and 350 N at T10-T11 (2-level tethers), fused (T10-L2)xa0+ hand-tied suture loop through the spinous processes at T9-T10 (suture loop), and fused (T10-L2) with the T9-T10 interspinous and supraspinous ligaments cut (cut ISL/SSL).nnnRESULTSnThe flexion range of motion (ROM) at T9-T10 of the fused spine, loaded at 8 Nm, increased to 162% of the native spine loaded at 4 Nm. The average flexion ROM at T9-T10 for tethers 250 N, tethers 350 N, 2-level tethers, suture loop, and cut ISL/SSL were 85% (P < 0.0001), 70% (Pxa0< 0.0001), 93% (P < 0.0001), 141% (Pxa0= 0.13), and 177% (Pxa0= 0.66) of the native spine at 4 Nm, respectively (Pxa0values vs. fused).nnnCONCLUSIONSnSublaminar polyester bands can modulate the biomechanical flexion ROM as a function of the band pretension and provide a more consistent and tunable technique than hand-tying a suture loop between the spinous processes.

Predictive Risk Factors of Nonhome Discharge Following Elective Posterior Cervical Fusion

OBJECTIVEnTo identify risk factors that are predictive of nonhome discharge after elective posterior cervical fusion.nnnMETHODSnWe performed a retrospective cohort study of adult patients who underwent elective posterior cervical fusion using the American College of Surgeons National Surgical Quality Improvement Program database from 2010 to 2014. Patients were divided into 2 groups: home discharge and nonhome discharge. Univariate analysis was performed to compare incidence of 30-day postoperative complications between groups. Multivariate analysis was performed to identify complications that were predictive of nonhome discharge.nnnRESULTSnThe cohort included 2875 patients; 24.1% were discharged to a nonhome facility, including skilled and nonskilled care facilities, nursing homes, assisted living facilities, and rehabilitation facilities. Nonhome discharge was associated with higher rates of 30-day pulmonary complication, cardiac complication, venous thromboembolism, urinary tract infection, blood transfusion, sepsis, and reoperation. Significant predictors of nonhome discharge were wound complication (odds ratio [OR]xa0= 1.73; 95% confidence interval [CI], 1.07-2.80; Pxa0= 0.024), pulmonary complication (ORxa0= 3.61; 95% CI, 1.96-6.63; Pxa0<xa00.001), cardiac complication (ORxa0= 6.13; 95% CI, 1.61-23.4; Pxa0= 0.008), venous thromboembolism (ORxa0= 2.97; 95% CI, 1.43-6.19; Pxa0=xa00.004), urinary tract infection (ORxa0= 2.69; 95% CI, 1.50-4.82; P < 0.001), blood transfusion (ORxa0= 1.70; 95% CI, 1.20-2.39; Pxa0= 0.003), sepsis (ORxa0= 2.75; 95% CI, 1.25-6.02; Pxa0= 0.012), and prolonged length of stay (ORxa0= 4.07; 95% CI, 3.34-4.95; P < 0.001).nnnCONCLUSIONSnEarly identification of patients who are at high risk for nonhome discharge is important to implement early comprehensive discharge planning protocols and minimize hospital-acquired conditions related to prolonged length of stay and associated health care costs.

Anterior Lumbar Fusion: Differences in Patient Selection and Surgical Outcomes Between Neurosurgeons and Orthopaedic Surgeons

OBJECTIVEnAnterior lumbar fusion (ALF) is performed by both neurosurgeons and orthopaedic surgeons. The aim of this study was to determine differences between the 2 surgical subspecialties in terms of patient selection and postoperative outcomes after ALF.nnnMETHODSnA retrospective cohort study of adult patients undergoing ALF in the American College of Surgeons National Surgical Quality Improvement Program database from 2010 to 2014 was performed. Univariate analyses were performed to identify differences in baseline patient demographics, comorbidities, operative characteristics, and 30-day postoperative outcomes between neurosurgery and orthopaedic surgery patients. Multivariate logistic regression analysis was used to determine whether surgical subspecialty was an independent risk factor for postoperative complications.nnnRESULTSnThe study included 3182 patients, with 1629 (51.2%) neurosurgery patients and 1553 (48.8%) orthopaedic surgery patients. A greater proportion of neurosurgery patients were >65 years old, were being treated with preoperative steroids, had cardiac or pulmonary comorbidities, and had an American Society of Anesthesiologists classification III or higher. ALF procedures performed by neurosurgeons more frequently involved use of intervertebral devices and bone graft. On multivariate logistic regression analysis, ALF procedures performed by neurosurgeons were independently associated with a higher risk of reoperation (odds ratioxa0= 1.61; 95% confidence interval, 1.02-2.56; Pxa0= 0.042) and urinary tract infection (odds ratioxa0= 1.94; 95% confidence interval, 1.02-3.68; Pxa0= 0.043).nnnCONCLUSIONSnIn addition to differences in baseline patient demographics and comorbidities and operative characteristics, ALF performed by neurosurgeons had a higher risk of 30-day reoperation and urinary tract infection compared with ALF performed by orthopaedic surgeons.

Risk Factors for Perioperative Blood Transfusions in Adult Spinal Deformity Surgery.

OBJECTIVEnAdult spinal deformity (ASD) surgery is associated with a high rate of perioperative blood transfusions, and it is important to understand the risk factors for perioperative blood transfusions to implement strategies to reduce transfusions. The aim of this study was to identify independent risk factors of perioperative blood transfusions in patients undergoing surgery for ASD.nnnMETHODSnA retrospective cohort study was performed using the American College of Surgeons National Surgical Quality Improvement Program database from 2010 to 2014. Adult patients undergoing surgery for ASD were separated into 2 cohorts based on whether they received a perioperative blood transfusion. Univariate and multivariate regression models were used to identify risk factors for blood transfusion.nnnRESULTSnIn our cohort of 5805 patients, 27.1% received a blood transfusion. Multivariate regression analysis showed that patient-specific risk factors were age 65 years or older (odds ratio [OR], 1.74; 95% confidence interval [CI], 1.49-2.03; P < 0.001), American Society of Anesthesiologists classification of 3 or greater (OR, 1.18; 95% CI, 1.01-1.37; Pxa0= 0.033), cardiac comorbidity (OR, 1.21; 95% CI, 1.03-1.41; Pxa0= 0.018) and bleeding disorder (OR, 2.01; 95% CI, 1.10-3.66; Pxa0= 0.023). Surgery-specific risk factors were a posterior approach (OR, 4.25; 95% CI, 3.46-5.22; Pxa0<xa00.001), pelvic fixation (OR, 1.73; 95% CI, 1.36-2.20; Pxa0<xa00.001), and osteotomy (OR, 2.08; 95% CI, 1.71-2.51; P < 0.001). Longer operative time was also a risk factor with a duration-dependent effect on the odds of blood transfusion.nnnCONCLUSIONSnRecognition of patient- and surgery-specific risk factors for perioperative blood transfusion is important to identify patients who are at high risk and to implement strategies to minimize intraoperative blood loss and decrease healthcare costs.

Comparison of Anterior Cervical Discectomy and Fusion With a Stand-Alone Interbody Cage Versus a Conventional Cage-Plate Technique: A Systematic Review and Meta-Analysis

Study Design: Systematic review and meta-analysis. Objective: Compare the clinical and radiographic outcomes of anterior cervical discectomy and fusion (ACDF) with a stand-alone interbody cage versus a conventional cage and anterior cervical plate technique. Methods: A systematic Medline search was conducted using PubMed, EMBASE, and Cochrane Library Database of Systematic Reviews. Search terms included “anterior cervical discectomy and fusion,” “cage,” and “bone plates,” or variations thereof. Only studies involving a direct comparison of ACDF with a stand-alone cage versus a cage and plate were included. From the selected studies, we extracted data on patient demographics, comorbidities, surgical risk factors, and pre- and postoperative radiographic findings. A meta-analysis was performed on all outcome measures. The quality of each study was assessed using the Downs and Black checklist. Results: Nineteen studies met the inclusion and exclusion criteria. Patients who underwent ACDF with a cage-only technique had significantly lower rates of postoperative dysphagia and adjacent segment disease compared with patients who underwent ACDF with a cage-plate technique. However, patients who underwent ACDF with a cage-plate technique had better radiographic outcomes with significantly less subsidence and better restoration of cervical lordosis. There were no other significant differences in outcomes or postoperative complications. Conclusions: ACDF with a cage-only technique appears to have better clinical outcomes than the cage-plate technique, despite radiographic findings of increased rates of subsidence and less restoration of cervical lordosis. Future randomized controlled trials with longer term follow-up are needed to confirm the findings of this meta-analysis.

Thirty-Day Perioperative Complications, Prolonged Length of Stay, and Readmission Following Elective Posterior Lumbar Fusion Associated With Poor Nutritional Status

Study Design: Retrospective study. Objective: To determine the rates of early postoperative mortality and morbidity in adults with hypoalbuminemia undergoing elective posterior lumbar fusion (PLF). Methods: The American College of Surgeons National Surgical Quality Improvement Program (ACS NSQIP) was examined from 2005 to 2012. Current Procedural Terminology (CPT) codes were used to query the database for adults (≥18 years) who underwent PLF and/or posterior/transforaminal lumbar interbody fusion (PLIF/TLIF). Patients were divided into those with normal albumin concentration (≥3.5g/dL) and those with hypoalbuminemia (<3.5 g/dL). Both univariate and multivariate analyses were performed. Results: A total of 2410 patients were included, of whom 2251 (93.4%) were normoalbuminemic and 159 (6.6%) were hypoalbuminemic. Patients with preoperative serum albumin levels <3.5 g/dL were older with a higher American Society of Anesthesiologists (ASA) score, and more comorbidities, including anemia, diabetes, dependent functional status, and preoperative history of chronic steroid therapy. Hypoalbuminemic patients had higher rates of any 30-day perioperative complication (P < .001), unplanned readmission (P = .019), and prolonged length of stay (LOS) >5 days (P < .001). However, hypoalbuminemia was not significantly associated with any specific perioperative complication. On multivariate analysis, preoperative hypoalbuminemia was found to be an independent predictor of prolonged LOS (OR 2.4, 95% CI 1.7-3.5; P < .001) and unplanned readmission (OR 2.7, 95% CI 1.1-6.3; P = .023). Conclusion: Hypoalbuminemia was found to be an important predictor of patient outcomes in this population. This study suggests that clinicians should consider nutritional screening and optimization as part of the preoperative risk assessment algorithm. Level of Evidence: III

Primary Versus Revision Discectomy for Adults With Herniated Nucleus Pulposus: A Propensity Score–Matched Multicenter Study

Study Design: Retrospective propensity score matched analysis. Objective: To compare the incidence of any 30-day perioperative complication following primary and revision discectomy for lumbar disc herniation. Methods: The American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) was used to identify patients undergoing primary or revision lumbar discectomy from 2005 to 2012. Propensity score matching was performed to create matched pairs of primary and revision discectomy cases for analysis. Univariate analysis was then performed to compare 30-day morbidity and mortality between propensity score–matched pairs. Results: We identified 4730 cases of primary discectomy performed through a minimally invasive or open approach and 649 revision discectomy cases. Baseline patient characteristics and comorbidities were compared and then propensity score–matched adjustments were made to create 649 matched pairs of primary and revision cases. On univariate analysis, there were no significant differences in 30-day perioperative outcomes between the 2 groups. Conclusion: While there were no significant differences in 30-day perioperative complications between patients undergoing primary lumbar discectomy and those undergoing revision lumbar discectomy, this finding should be interpreted with caution since the ACS-NSQIP database lacks functional and pain outcomes, and also does not include dural tear or durotomy as a complication. Future large-scale and long-term prospective studies including these variables are needed to better understand the outcomes and complications following primary versus revision discectomy for lumbar disc herniation.

Age Stratification of 30-Day Postoperative Outcomes Following Excisional Laminectomy for Extradural Cervical and Thoracic Tumors:

Study Design: Retrospective cohort study. Objectives: To evaluate age as an independent predictive factor for perioperative morbidity and mortality in patients undergoing surgical decompression for metastatic cervical and thoracic spinal tumors using the American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) database from 2011 to 2014. Methods: We identified 1673 adult patients undergoing excisional laminectomy of cervical and thoracic extradural tumors. Patients were stratified into quartiles based on age, with Q1 including patients aged 18 to 49 years, Q2 including patients aged 50 to 60 years, Q3 including patients aged 61 to 69 years, and Q4 including patients ≥70 years. Univariate and multivariate regression analyses were performed to examine the association between age and 30-day perioperative morbidity and mortality. Results: Age was an independent risk factor for 30-day venous thromboembolism (VTE) and reoperation. Patients in Q3 for age had nearly a 4 times increased risk of VTE than patients in Q1 (odds ratio [OR] 3.97; 95% CI 1.91-8.25; P < .001). However, there was no significant difference in VTE between patients in Q4 and Q1 (P = .069). Patients in Q2 (OR 1.99; 95% CI 1.06-3.74; P = .032) and Q4 (OR 2.18; 95% CI 1.06-4.52; P = .036) for age had a 2 times increased risk of reoperation compared with patients in Q1. Conclusions: Age was an independent predictive factor for perioperative VTE and reoperation, but there was no clear age-dependent relationship between increasing age and the risk of these perioperative complications.

Impact of Obesity on Surgical Outcomes Following Laminectomy for Spinal Metastases

Study Design: Retrospective cohort study. Objectives: To determine the effect of obesity (body mass index >30 kg/m2) on perioperative morbidity and mortality after surgical decompression of spinal metastases. Methods: The American College of Surgeons National Surgical Quality Improvement Program database is a large multicenter clinical registry that collects preoperative risk factors, intraoperative variables, and 30-day postoperative morbidity and mortality outcomes from hospitals nationwide. Current Procedural Terminology codes were used to query the database for adults who underwent decompression with laminectomy for treatment of metastatic spinal lesions between 2010 and 2014. Patients were separated into 2 cohorts based on the presence of absence of obesity. Univariate analysis and multivariate logistic regression analysis were used to analyze the effect of obesity on perioperative morbidity and mortality. Results: There was a significantly higher rate of venous thromboembolism (VTE; obese 6.6% vs nonobese 4.2%; P = .01) and pulmonary complications (obese 2.6% vs nonobese 2.2%; P = .046) in the obese group compared with the nonobese group. The nonobese group had prolonged hospitalization (obese 62.0% vs nonobese 69.0%; P = .001) and a higher incidence of blood transfusions (obese 26.8% vs nonobese 34.2%; P < .001). On multivariate analysis, obesity was found to be an independent risk factor for VTE (odds ratio = 1.75, confidence interval = 1.17-2.63, P = .007). Conclusions: Obese patients were predisposed to an elevated risk of VTE following laminectomy for spinal metastases. Early postoperative mobilization and a low threshold to evaluate for perioperative VTE are important in these patients in order to appropriately diagnose and treat these complications and minimize morbidity.

Risk Factors for Perioperative Complications in Morbidly Obese Patients Undergoing Elective Posterior Lumbar Fusion

Study Design: Retrospective cohort study. Objectives: The prevalence of obesity-related low back pain and degenerative disc disease is on the rise. Past studies have demonstrated that obesity is associated with higher perioperative complication rates, but there remains a gap in the literature regarding additional risk factors that further predispose this already high-risk patient population to poor surgical outcomes following elective posterior lumbar fusion (PLF). The aim of the study is to identify independent risk factors for poor 30-day perioperative outcomes in morbidly obese patients undergoing elective PLF. Methods: We identified 22u2009909 patients in the American College of Surgeons National Surgical Quality Improvement Program database who underwent elective PLF. There were 1861 morbidly obese patients. Baseline patient demographics and medical comorbidities were collected. Univariate analysis was performed to compare perioperative complication rates between non-morbidly obese and morbidly obese patients. The 5 most common complications in the morbidly obese group were then selected for multivariate regression analysis to identify independent risk factors for poor 30-day outcomes. Results: Morbidly obese patients had a higher perioperative complication rate. The 5 most common complications were prolonged hospitalization, blood transfusion, readmission, wound complications, and reoperation. Independent risk factors for these complications were age ≥65 years, super obesity (ie, BMI > 48.6), chronic steroid use, American Society of Anesthesiology classification ≥3, poor functional status, long length of fusion ≥4 levels, and extended operative time (ie, operative time ≥318 minutes). Conclusions: Morbidly obese patients are at higher risk of perioperative complications following elective PLF. Modifiable risk factors for the most common complications are obesity and preoperative steroid use.