Complications Associated With Ventriculoperitoneal Shunt Surgery for Normal Pressure Hydrocephalus Using Stereotactic Navigation and Abdominal Laparoscopy: A Single-Institution Case Series.

BACKGROUND: Normal pressure hydrocephalus (NPH) is characterized by cerebral ventriculomegaly and the triad of magnetic gait, urinary incontinence, and cognitive impairment. Treatment includes ventriculoperitoneal (VP) shunt surgery. OBJECTIVE: To evaluate complication rates in a cohort of patients undergoing VP shunt surgery with stereotactic proximal catheter navigation and laparoscopic distal catheter placement. METHODS: This study was a retrospective consecutive cohort analysis of 117 patients with NPH undergoing VP shunt placement using both stereotactic navigation and laparoscopy from 2015 to 2020. Patients with obstructive hydrocephalus and those with central nervous system infection, intraventricular hemorrhage, Ommaya reservoirs, or undergoing shunt revision at initial encounter were excluded. Variables included demographics and comorbidities, NPH symptoms, operative details, radiographic outcomes, and rates of complications, readmissions, and reoperations within 1, 3, and 12 months. Impact of demographics and comorbidities on complication rates was assessed using Fisher exact tests. RESULTS: Zero patients required reoperation within 30 days. One intracranial hemorrhage was detected on immediate postoperative head computed tomography. Four patients ultimately required revision: 2 for catheter repositioning to alleviate abdominal pain, 1 ligation for a colectomy, and 1 removal for shunt infection. Patients with cardiac or other neurological comorbidities had higher rates of readmission and complications. Systemic complications totaled 12% in the first 30 days. CONCLUSION: The combination of intraoperative stereotactic navigation and laparoscopic assistance leads to low rates of serious complications and reoperations for VP shunt implantation in patients with NPH. These changes to surgical technique are easy to implement and may reduce the risk for this common operation.

Does Stereoelectroencephalography Add Value in Patients with Lesional Epilepsy?

OBJECTIVE: Stereoelectroencephalography (SEEG) has gained popularity as an invasive monitoring modality for epileptogenic zone (EZ) localization. The need and indications for SEEG in patients with evident brain lesions or associated abnormalities on imaging is debated. We report our experience with SEEG as a presurgical evaluation tool for patients with lesional epilepsy. METHODS: A retrospective cohort study was performed of 131 patients with lesional or magnetic resonance imaging abnormality-associated medically refractory focal epilepsy who underwent resections from 2010 to 2017. Seventy-one patients had SEEG followed by resection, and 60 had no invasive recordings. Volumetric analysis of resection cavities from 3T magnetic resonance imaging was performed. RESULTS: Mean lesion and resection volumes for SEEG and non-SEEG were 16.2 (standard deviation [SD] = 29) versus 23.7 cm3 (SD = 38.4) and 28.1 (SD = 23.2) versus 43.6 cm3 (SD = 43.5), respectively (P = 0.009). Comparing patients with seizure recurrence and patients who remained seizure free, significantly associated variables with seizure recurrence included mean number of failed antiseizure medications (6.86 [SD = 0.32] vs. 5.75 [SD = 0.32]; P = 0.01) and in SEEG patients the mean number of electrodes implanted (8.1 [SD = 0.8] vs. 5.0 [SD = 0.8]; P = 0.005). After multivariate analysis, only failed numbers of medication remained significantly associated with seizure recurrence. CONCLUSIONS: Seizure outcomes did not correlate with final resection volume after SEEG evaluation. SEEG evaluation presurgically can be used to maintain the efficacy of resection and decrease the volume and subsequent risk of extensive tissue removal. We believe that this technology allows resective surgery to proceed in a subpopulation of patients with lesional epilepsy who may otherwise not have been considered surgical candidates.

Simple and actionable preoperative prediction of postoperative healthcare needs of single-level lumbar fusion patients.

OBJECTIVE: Preoperative prediction of a patient's postoperative healthcare utilization is challenging, and limited guidance currently exists. The objective of the present study was to assess the capability of individual risk-related patient characteristics, which are available preoperatively, that may predict discharge disposition prior to lumbar fusion. METHODS: In total, 1066 consecutive patients who underwent single-level, posterior-only lumbar fusion at a university health system were enrolled. Patients were prospectively asked 4 nondemographic questions from the Risk Assessment and Prediction Tool during preoperative office visits to evaluate key risk-related characteristics: baseline walking ability, use of a gait assistive device, reliance on community supports (e.g., Meals on Wheels), and availability of a postoperative home caretaker. The primary outcome was discharge disposition (home vs skilled nursing facility/acute rehabilitation). Logistic regression was performed to analyze the ability of each risk-related characteristic to predict likelihood of home discharge. RESULTS: Regression analysis demonstrated that improved baseline walking ability (OR 3.17), ambulation without a gait assistive device (OR 3.13), and availability of a postoperative home caretaker (OR 1.99) each significantly predicted an increased likelihood of home discharge (all p < 0.0001). However, reliance on community supports did not significantly predict discharge disposition (p = 0.94). CONCLUSIONS: Patient mobility and the availability of a postoperative caretaker, when determined preoperatively, strongly predict a patient's healthcare utilization in the setting of single-level, posterior lumbar fusion. These findings may help surgeons to streamline preoperative clinic workflow and support the patients at highest risk in a targeted fashion.

Quality-of-life and postoperative satisfaction following pseudoarthrectomy in patients with Bertolotti syndrome.

BACKGROUND CONTEXT: Bertolotti syndrome is a clinical diagnosis given to patients with back pain arising from a lumbosacral transitional vertebra (LSTV). A particular class of LSTV involves a pseudoarticulation between the fifth lumbar transverse process and the sacral ala, and surgical resection of the pseudoarticulation may be offered to patients failing conservative management. Bertolotti syndrome is still not well understood, particularly regarding how patients respond to surgical resection of the LSTV pseudoarticulation. PURPOSE: To examine change in quality-of-life (QOL) and patient satisfaction following surgical resection of the LSTV pseudoarticulation in patients with Bertolotti syndrome. DESIGN: Ambidirectional observational cohort study of patients seen at a single institution's tertiary spine center over a 10-year period. PATIENT SAMPLE: Cohort consisted of 31 patients with Bertolotti Syndrome who underwent surgical resection of the pseudoarticulation. OUTCOME MEASURES: Preoperative and postoperative Patient-Reported Outcomes Measurement Information System Global Health (PROMIS-GH) Mental and Physical Health T-scores, and a single-item postoperative satisfaction questionnaire. METHODS: Patients were identified through diagnostic and procedural codes. Immediate preoperative PROMIS-GH scores available in the chart were gathered retrospectively, and postoperative PROMIS-GH and satisfaction scores were gathered prospectively through a mail-in survey. RESULTS: Mean (SD) improvement of PROMIS-GH Physical Health T-score was 8.7 (10.5) (p<.001). Mean (SD) improvement of PROMIS-GH Mental Health T-scores was 5.9 (9.2) (p=.001). When stratifying PROMIS-GH T-scores by response to the patient satisfaction survey, there were significant group differences in mean change for Physical Health T-scores (p<.001), and Mental Health T-score (p=.009). Patients who stated, "The treatment met my expectations" had much greater mean improvement in the PROMIS-GH T-scores. CONCLUSIONS: Patients undergoing a pseudoarticulation resection procedure may experience a significant improvement in quality-of-life as measured by PROMIS-GH Mental and Physical Health.

A Novel and Inexpensive Technique for High-Tension Tendon Clamping With Expandable Mesh Sleeving for In Vitro Foot Biomechanics Testing.

In vitro biomechanical testing is common in the field of orthopedics when novel devices are investigated prior to human trials. It is typically necessary to apply loads through tendons to simulate normal activities, such as walking during a foot and ankle study. However, attachment of tendons to linear actuators has proven challenging because of the tendency of clamps to either slip off or rupture the tendon. Various techniques have been utilized. Freeze clamping is generally accepted as the gold standard for very high load testing in excess of 3000 N, but is expensive, time-consuming, and requires significant ancillary equipment. Purely mechanical solutions such as metal jaw clamps, wire meshes, and others have been explored, but these techniques are either costly, have low load capacities, or have not proven to be reproducible. We have developed a novel tendon clamping technique that utilizes a slip-resistant polyester mesh sleeving that encases the tendon and is fixated at the bottom of the tendon/sleeve interaction with a giftbox suture. The loose end of the sleeving can then be tied in to the linear actuator or load cell apparatus using a timber hitch knot. The sleeving technique allows for loads of 2000-2500 N on the Achilles tendon, and is inexpensive, reproducible, and can be modified to apply loads to smaller tendons as well, though a length of tendon/sleeve overlap of at least 16 cm is required to reach maximum loads. This technique should assist researchers in integrating muscle forces into future biomechanical study designs.

Estimating the Risk of Deep Brain Stimulation in the Modern Era: 2008 to 2020.

BACKGROUND: Deep brain stimulation (DBS) was first approved by the United States Food and Drug Administration in 1997. Although the fundamentals of DBS remain the same, hardware, software, and imaging have evolved significantly. OBJECTIVE: To test our hypothesis that the aggregate complication rate in the medical literature in the past 12 years would be lower than what is often cited based on early experience with DBS surgery. METHODS: PubMed, PsycINFO, and EMBASE were queried for studies from 2008 to 2020 that included patients treated with DBS from 2007 to 2019. This yielded 34 articles that evaluated all complications of DBS surgery, totaling 2249 patients. RESULTS: The overall complication rate in this study was 16.7% per patient. There was found to be a systemic complication rate of 0.89%, intracranial complication rate of 2.7%, neurological complication rate of 4.6%, hardware complication rate of 2.2%, and surgical site complication rate of 3.4%. The infection and erosion rate was 3.0%. CONCLUSION: This review suggests that surgical complication rates have decreased since the first decade after DBS was first FDA approved. Understanding how to minimize complications from the inception of a technique should receive more attention.

Osteobiologics.

BACKGROUND: Osteobiologics are engineered materials that facilitate bone healing and have been increasingly used in spine surgery. Autologous iliac crest bone grafts have been used historically, but morbidity associated with graft harvesting has led surgeons to seek alternative solutions. Allograft bone, biomaterial scaffolds, growth factors, and stem cells have been explored as bone graft substitutes and supplements. OBJECTIVE: To review current and emerging osteobiologic technologies. METHODS: A literature review of English-language studies was performed in PubMed. Search terms included combinations of "spine," "fusion," "osteobiologics," "autologous," "allogen(e)ic," "graft," "scaffold," "bone morphogenic protein," and "stem cells." RESULTS: Evidence supports allograft bone as an autologous bone supplement or replacement in scenarios where minimal autologous bone is available. There are promising data on ceramics and P-15; however, comparative human trials remain scarce. Growth factors, including recombinant human bone morphogenic proteins (rhBMPs) 2 and 7, have been explored in humans after successful animal trials. Evidence continues to support the use of rhBMP-2 in lumbar fusion in patient populations with poor bone quality or revision surgery, while there is limited evidence for rhBMP-7. Stem cells have been incredibly promising in promoting fusion in animal models, but human trials to this point have only involved products with questionable stem cell content, thereby limiting possible conclusions. CONCLUSION: Engineered stem cells that overexpress osteoinductive factors are likely the future of spine fusion, but issues with applying viral vector-transduced stem cells in humans have limited progress.

A Retrospective Cohort Study of Effects of Antihypertensive and Anticholinergic Medications on Outcomes Following Elective Posterior Lumbar Spine Surgery.

STUDY DESIGN: This was a retrospective consecutive cohort analysis. OBJECTIVE: This study aimed to examine the association between commonly prescribed medications and outcomes following posterior lumbar spine surgery. SUMMARY OF BACKGROUND DATA: Postoperative complications and prolonged length of stay significantly increase costs following posterior lumbar spine surgery and worsen patient outcomes. To control costs and complications, providers should focus on modifiable risk factors, such as preoperative medications. Antihypertensive and anticholinergic drugs are among the most commonly prescribed medications but can carry significant risks in the perioperative period. MATERIALS AND METHODS: This study was a retrospective cohort analysis of patients undergoing posterior lumbar spine surgery from January 2014 through December 2015 at a large tertiary care center. The variable selection followed by multivariable logistic and negative binomial regressions were performed. An α threshold of 0.0056 was used for significance after correction for multiple comparisons. A secondary analysis was performed to evaluate confounding or effect modifying variables. RESULTS: This study included 1577 patients. Postoperative urinary retention risk was increased in patients taking loop diuretics. Acute kidney injury risk was increased for patients on nondihydropyridine calcium-channel blockers. Surgical site infection risk was increased for patients on aldosterone receptor blockers. Urinary tract infection risk was increased for patients on anticholinergics for urinary incontinence. Length of stay was decreased for patients on angiotensin II antagonists and angiotensin-converting enzyme inhibitors. CONCLUSION: A care path should be established in the perioperative period for patients who are deemed to be at higher risk due to medication status to either modify medications or improve postoperative monitoring. LEVEL OF EVIDENCE: Level III.

What Demographic and Clinical Factors Are Associated with In-hospital Mortality in Patients with Necrotizing Fasciitis?

BACKGROUND: Necrotizing fasciitis is a rare infection with rapid deterioration and a high mortality rate. Factors associated with in-hospital mortality have not been thoroughly evaluated. Although predictive models identifying the diagnosis of necrotizing fasciitis have been described (such as the Laboratory Risk Indicator for Necrotizing Fasciitis [LRINEC]), their use in predicting mortality is limited. QUESTIONS/PURPOSES: (1) What demographic factors are associated with in-hospital mortality in patients with necrotizing fasciitis? (2) What clinical factors are associated with in-hospital mortality? (3) What laboratory values are associated with in-hospital mortality? (4) Is the LRINEC score useful in predicting mortality? METHODS: We retrospectively studied all patients with necrotizing fasciitis at our tertiary care institution during a 10-year period. In all, 134 patients were identified; after filtering out patients with missing data (seven) and those without histologically confirmed necrotizing fasciitis (12), 115 patients remained. These patients were treated with early-initiation antibiotic therapy and aggressive surgical intervention once the diagnosis was suspected. Demographic data, clinical features, laboratory results, and treatment variables were identified. The median age was 56 years and 42% of patients were female. Of the 115 patients analyzed, 15% (17) died in the hospital. Univariate and receiver operating characteristic analyses were performed due to the low number of mortality events seen in this cohort. RESULTS: The demographic factors associated with in-hospital mortality were older age (median: 64 years for nonsurvivors [interquartile range (IQR) 57-79] versus 55 years for survivors [IQR 45-63]; p = 0.002), coronary artery disease (odds ratio 4.56 [95% confidence interval (CI) 1.51 to 14]; p = 0.008), chronic kidney disease (OR 4.92 [95% CI 1.62 to 15]; p = 0.006), and transfer from an outside hospital (OR 3.47 [95% CI 1.19 to 10]; p = 0.02). The presenting clinical characteristics associated with in-hospital mortality were positive initial blood culture results (OR 4.76 [95% CI 1.59 to 15]; p = 0.01), lactic acidosis (OR 4.33 [95% CI 1.42 to 16]; p = 0.02), and multiple organ dysfunction syndrome (OR 6.37 [95% CI 2.05 to 20]; p = 0.002). Laboratory values at initial presentation that were associated with in-hospital mortality were platelet count (difference of medians -136 [95% CI -203 to -70]; p < 0.001), serum pH (difference of medians -0.13 [95% CI -0.21 to -0.03]; p = 0.02), serum lactate (difference of medians 0.90 [95% CI 0.40 to 4.80]; p < 0.001), serum creatinine (difference of medians 1.93 [95% CI 0.65 to 3.44]; p < 0.001), partial thromboplastin time (difference of medians 8.30 [95% CI 1.85 to 13]; p = 0.03), and international normalized ratio (difference of medians 0.1 [95% CI 0.0 to 0.5]; p = 0.004). The LRINEC score was a poor predictor of mortality with an area under the receiver operating characteristics curve of 0.56 [95% CI 0.45-0.67]. CONCLUSIONS: Factors aiding clinical recognition of necrotizing fasciitis are not consistently helpful in predicting mortality of this infection. Identifying patients with potentially compromised organ function should lead to aggressive and expedited measures for diagnosis and treatment. Future multicenter studies with larger populations and a standardized algorithm of treatment triggered by high clinical suspicion can be used to validate these findings to better help prognosticate this potentially fatal diagnosis.Level of Evidence Level III, therapeutic study.

Correction to: Removal of a urinary catheter before discontinuation of epidural analgesia is associated with an increased risk of postoperative urinary retention and hospital episode costs in patients undergoing surgical correction for adolescent idiopathic scoliosis.

The original version of this article unfortunately contained a mistake. The spelling of Erin Ohliger's name was incorrect.

Predictors of second-sided deep brain stimulation for Parkinson's disease.

OBJECTIVE: Parkinson's disease (PD) is a progressive neurological movement disorder that is commonly treated with deep brain stimulation (DBS) surgery in advanced stages. The purpose of this study was to investigate factors that affect time to placement of a second-sided DBS lead for PD when a unilateral lead is initially placed for asymmetrical presentation. The decision whether to initially perform unilateral or bilateral DBS is largely based on physician and/or patient preference. METHODS: This study was a retrospective cohort analysis of patients with PD undergoing initial unilateral DBS for asymmetrical disease between January 1999 and December 2017 at the authors' institution. Patients treated with DBS for essential tremor or other conditions were excluded. Variables collected included demographics at surgery, time since diagnosis, Unified Parkinson's Disease Rating Scale motor scores (UPDRS-III), patient-reported quality-of-life outcomes, side of operation, DBS target, intraoperative complications, and date of follow-up. Paired t-tests were used to assess mean changes in UPDRS-III. Cox proportional hazards analysis and the Kaplan-Meier method were used to determine factors associated with time to second lead insertion over 5 years. RESULTS: The final cohort included 105 patients who underwent initial unilateral DBS for asymmetrical PD; 59% of patients had a second-sided lead placed within 5 years with a median time of 34 months. Factors found to be significantly associated with early second-sided DBS included patient age 65 years or younger, globus pallidus internus (GPi) target, and greater off-medication reduction in UPDRS-III score following initial surgery. Older age was also found to be associated with a smaller preoperative UPDRS-III levodopa responsiveness score and with a smaller preoperative to postoperative medication-off UPDRS-III change. CONCLUSIONS: Younger patients, those undergoing GPi-targeted unilateral DBS, and patients who responded better to the initial DBS were more likely to undergo early second-sided lead placement. Therefore, these patients, and patients who are more responsive to medication preoperatively (as a proxy for DBS responsiveness), may benefit from consideration of initial bilateral DBS.

Removal of a urinary catheter before discontinuation of epidural analgesia is associated with an increased risk of postoperative urinary retention and hospital episode costs in patients undergoing surgical correction for adolescent idiopathic scoliosis.

OBJECTIVES: In adolescent idiopathic scoliosis (AIS) patients undergoing posterior spinal instrumented fusion (PSIF), we aimed to answer these questions: (1) is there a difference in postoperative urinary retention (UR) rates among patients who had removal of their Foley catheters before vs. after discontinuation of epidural analgesia (EA)? (2) Can the timing of Foley catheter removal be an independent risk factor for postoperative UR requiring recatheterization? (3) Is there an incurred cost related to treating UR? STUDY DESIGN: Retrospective cohort. BACKGROUND: EA has been widely used for postoperative pain control after PSIF for AIS. In these patients, removing the Foley catheter, inserted for intraoperative monitoring of urine output, is indicated in the early postoperative period. However, a controversy exists as to whether it should be removed before or after the EA has been discontinued. METHODS: A single-institution, longitudinally maintained database was queried to identify 297 patients who met specific inclusion and exclusion criteria. Patient characteristics and the order and timing of removing the urinary and epidural catheters were collected. Rates of UR were statistically compared in patients who had early vs. late urinary catheter removal. A univariate and multivariate regression analysis was conducted to identify independent risk factors. Hospital episode costs were analyzed. RESULTS: Patients who had early (n = 66, 22%) vs. late (n = 231, 78%) urinary catheter removal had a significantly higher incidence of UR requiring recatheterization (15 vs. 4.7%, p = 0.007). Patient with early removal were almost 4 times more likely to develop UR requiring recatheterization [odds ratio (OR) 3.8, 95% confidence interval (CI) 1.5-9.7, p = 0.005]. UR incurred additional costs averaging $15,000/patient (p = 0.204). CONCLUSION: In patients who had PSIF for AIS, removal of a urinary catheter before discontinuation of EA is an independent risk factor for UR, requiring recatheterization and associated with increased cost. LEVEL OF EVIDENCE: III.

Can a machine learning model accurately predict patient resource utilization following lumbar spinal fusion?

BACKGROUND CONTEXT: With the increasing emphasis on value-based healthcare in Centers for Medicare and Medicaid Services reimbursement structures, bundled payment models have been adopted for many orthopedic procedures. Immense variability of patients across hospitals and providers makes these models potentially less viable in spine surgery. Machine-learning models have been shown reliable at predicting patient-specific outcomes following lumbar spine surgery and could, therefore, be applied to developing stratified bundled payment schemes. PURPOSE: (1) Can a Naïve Bayes machine-learning model accurately predict inpatient payments, length of stay (LOS), and discharge disposition, following dorsal and lumbar fusion? (2) Can such a model then be used to develop a risk-stratified payment scheme? STUDY DESIGN: A Naïve Bayes machine-learning model was constructed using an administrative database. PATIENT SAMPLE: Patients undergoing dorsal and lumbar fusion for nondeformity indications from 2009 through 2016 were included. Preoperative inputs included age group, gender, ethnicity, race, type of admission, All Patients Refined (APR) risk of mortality, APR severity of illness, and Clinical Classifications Software diagnosis code. OUTCOME MEASURES: Predicted resource utilization outcomes included LOS, discharge disposition, and total inpatient payments. Model validation was addressed via reliability, model output quality, and decision speed, based on application of training and validation sets. Risk-stratified payment models were developed according to APR risk of mortality and severity of illness. RESULTS: A Naïve Bayes machine-learning algorithm with adaptive boosting demonstrated high reliability and area under the receiver-operating characteristics curve of 0.880, 0.941, and 0.906 for cost, LOS, and discharge disposition, respectively. Patients with increased risk of mortality or severity of illness incurred costs resulting in greater inpatient payments in a patient-specific tiered bundled payment, reflecting increased risk on institutions caring for these patients. We found that a large range in expected payments due to individuals' preoperative comorbidities indicating an individualized risk-based model is warranted. CONCLUSIONS: A Naïve Bayes machine-learning model was shown to have good-to-excellent reliability and responsiveness for cost, LOS, and discharge disposition. Based on APR risk of mortality and APR severity of illness, there was a significant difference in episode costs from lowest to highest risk strata. After using normalized model error to develop a risk-adjusted proposed payment plan, it was found that institutions incur significantly more financial risk in flat bundled payment models for patients with higher rates of comorbidities.

Development of a novel in vitro cadaveric model for analysis of biomechanics and surgical treatment of Bertolotti syndrome.

BACKGROUND CONTEXT: Bertolotti syndrome (BS) is caused by pseudoarticulation between an aberrant L5 transverse process and the sacral ala, termed a lumbosacral transitional vertebra (LSTV). BS is thought to cause low back pain and is treated with resection or fusion, both of which have shown success. Acquiring cadavers with BS is challenging. Thus, we combined 3D printing, based on BS patient CT scans, with normal cadaveric spines to create a BS model. We then performed biomechanical testing to determine altered kinematics from LSTV with surgical interventions. Force sensing within the pseudojoint modeled nociception for different trajectories of motion and surgical conditions. PURPOSE: This study examines alterations in spinal biomechanics with LSTVs and with various surgical treatments for BS in order to learn more about pain and degeneration in this condition, in order to help optimize surgical decision-making. In addition, this study evaluates BS histology in order to better understand the pathology and to help define pain generators-if, indeed, they actually exist. STUDY DESIGN/SETTING: Model Development: A retrospective patient review of 25 patients was performed to determine the imaging criteria that defines the classical BS patient. Surgical tissue was extracted from four BS patients for 3D-printing material selection. Biomechanical Analysis. This was a prospective cadaveric biomechanical study of seven spines evaluating spinal motions, and loads, over various surgical conditions (intact, LSTV, and LSTV with various fusions). Additionally, forces at the LSTV joint were measured for the LSTV and LSTV with fusion condition. Histological Analysis: Histologic analysis was performed prospectively on the four surgical specimens from patients undergoing pseudoarthrectomy for BS at our institution to learn more about potential pain generators. PATIENT SAMPLE: The cadaveric portion of the study involved seven cadaveric spines. Four patients were prospectively recruited to have their surgical specimens assessed histologically and biomechanically for this study. Patients under the age of 18 were excluded. OUTCOME MEASURES: Physiological measures recorded in this study were broken down into histologic analysis, tissue biomechanical analysis, and joint biomechanical analysis. Histologic analysis included pathologist interpretation of Hematoxylin and Eosin staining, as well as S-100 staining. Tissue biomechanical analysis included stiffness measurements. Joint biomechanical analysis included range of motion, resultant torques, relative axis angles, and LSTV joint forces. METHODS: This study received funding from the American Academy of Neurology Medical Student Research Scholarship. Three authors hold intellectual property rights in the simVITRO robotic testing system. No other authors had relevant conflicts of interest for this study. CT images were segmented for a representative BS patient and cadaver spines. Customized cutting and drilling guides for LSTV attachment were created for individual cadavers. 3D-printed bone and cartilage structural properties were based on surgical specimen stiffness, and specimens underwent histologic analysis via Hematoxylin and Eosin, as well as S-100 staining. Joint biomechanical testing was performed on the robotic testing system for seven specimens. Force sensors detected forces in the LSTV joint. Kruskal-Wallis tests and Dunnett's tests were used for statistical analysis with significance bounded to p<.05. RESULTS: LSTV significantly reduces motion at the L5-S1 level, particularly in lateral bending and axial rotation. Meanwhile, the LSTV increases adjacent segment motion significantly at the L2-L3 level, whereas other levels have nonsignificant trends toward increased motion with LSTV alone. Fusion involving L4-S1 (L4-L5 and L5-S1) to treat adjacent level degeneration associated with an LSTV is associated with a significant increase in adjacent segment motion at all levels other than L5-S1 compared to LSTV alone. Fusion of L5-S1 alone with LSTV significantly increases L3-L4 adjacent segment motion compared to LSTV alone. Last, ipsilateral lateral bending with or without ipsilateral axial rotation produces the greatest force on the LSTV, and these forces are significantly reduced with L5-S1 fusion. CONCLUSIONS: BS significantly decreases L5-S1 mobility, and increases some adjacent segment motion, potentially causing patient activity restriction and discomfort. Ipsilateral lateral bending with or without ipsilateral axial rotation may cause the greatest discomfort overall in these patients, and fusion of the L5-S1 or L4-S1 levels may reduce pain associated with these motions. However, due to increased adjacent segment motion with fusions compared to LSTV alone, resection of the joint may be the better treatment option if the superior levels are not unstable preoperatively. CLINICAL SIGNIFICANCE: This study's results indicate that patients with BS have significantly altered spinal biomechanics and may develop pain due to increased loading forces at the LSTV joint with ipsilateral lateral bending and axial rotation. In addition, increased motion at superior levels when an LSTV is present may lead to degeneration over time. Based upon results of LSTV joint force testing, these patients' pain may be effectively treated surgically with LSTV resection or fusion involving the LSTV level if conservative management fails. Further studies are being pursued to evaluate the relationship between in vivo motion of BS patients, spinal and LSTV positioning, and pain generation to gain a better understanding of the exact source of pain in these patients. The methodologies utilized in this study can be extrapolated to recreate other spinal conditions that are poorly understood, and for which few native cadaveric specimens exist.

Understanding quality of life and treatment history of patients with Bertolotti syndrome compared with lumbosacral radiculopathy.

OBJECTIVEBertolotti syndrome is a rare spinal condition that causes low-back pain due to a lumbosacral transitional vertebra (LSTV), which is a pseudoarticulation between the fifth lumbar transverse process and the sacral ala. Bertolotti syndrome patients are rarely studied, particularly with regard to their quality of life. This study aimed to examine the quality of life and prior treatments in patients with Bertolotti syndrome at first presentation to the authors' center in comparison with those with lumbosacral radiculopathy.METHODSThis study was a retrospective cohort analysis of patients with Bertolotti syndrome and lumbosacral radiculopathy due to disc herniation seen at the authors' institution's spine center from 2005 through 2018. Diagnoses were confirmed with provider notes and imaging. Variables collected included demographics, diagnostic history, prior treatment, patient-reported quality of life metrics, and whether or not they underwent surgery at the authors' institution. Propensity score matching by age and sex was used to match lumbosacral radiculopathy patients to Bertolotti syndrome patients. Group comparisons were made using t-tests, Fisher's exact test, Mann-Whitney U-tests, Cox proportional hazards models, and linear regression models where variables found to be different at the univariate level were included as covariates.RESULTSThe final cohort included 22 patients with Bertolotti syndrome who had patient-reported outcomes data available and 46 propensity score-matched patients who had confirmed radiculopathy due to disc herniation. The authors found that Bertolotti syndrome patients had significantly more prior epidural steroid injections (ESIs) and a longer time from symptom onset to their first visit. Univariate analysis showed that Bertolotti syndrome patients had significantly worse Patient-Reported Outcomes Measurement Information System (PROMIS) mental health T-scores. Adjustment for prior ESIs and time from symptom onset revealed that Bertolotti syndrome patients also had significantly worse PROMIS physical health T-scores. Time to surgery and other quality of life metrics did not differ between groups.CONCLUSIONSPatients with Bertolotti syndrome undergo significantly longer workup and more ESIs and have worse physical and mental health scores than age- and sex-matched patients with lumbosacral radiculopathy. However, both groups of patients had mild depression and clinically meaningful reduction in their quality of life according to all instruments. This study shows that Bertolotti syndrome patients have a condition that affects them potentially more significantly than those with lumbosacral radiculopathy, and increased attention should be paid to these patients to improve their workup, diagnosis, and treatment.

The Role of Additional Spine Surgery in the Management of Failed Back Surgery Syndrome, Complex Regional Pain Syndrome, and Intractable Pain in the Setting of Previous or Concurrent Spinal Cord Stimulation: Indications and Outcomes.

OBJECTIVE: Spinal cord stimulation (SCS) is both relatively safe and reversible. Although SCS is generally regarded as a last resort, some of these patients will undergo additional spinal surgery after the device has been implanted or after its removal. We present a descriptive study of subsequent spinal surgery after SCS implantation. METHODS: A retrospective review of patients who had undergone percutaneous or paddle SCS lead placement at our institution from 2009 to 2016 was performed. Patients who had only undergone trials or who had not undergone spine surgery after SCS implantation were excluded. RESULTS: We identified 22 patients (5.7%) who had undergone spine surgery during the course of SCS treatment or after SCS removal, or both, of a total 383 patients who had undergone paddle and/or percutaneous SCS implantation. The most common additional spine interventions included lumbosacral decompression and fusion (n = 15; 42%). Of 36 surgeries, the most frequent indications for subsequent intervention were stenosis or restenosis (n = 16; 73%) and spine deformity (n = 6; 27%). The median EuroQol-5D index was 0.397 preoperatively and 0.678 postoperatively. CONCLUSIONS: To the best of our knowledge, the present study is the first to describe spine surgery in the setting of SCS implantation. Our results have indicated that spine surgery subsequent to, or concurrent with, SCS implantation appears to occur in few patients. Our study results suggest a modest improvement in quality of life outcomes. Therefore, clinicians should remember that patients might require further spine surgery despite the use of SCS implantation and, thus, might require reevaluation by the spine team.

Predictors of Extended Length of Hospital Stay in Adolescent Idiopathic Scoliosis Patients Undergoing Posterior Segmental Instrumented Fusion: An Analysis of 407 Surgeries Performed at a Large Academic Center.

STUDY DESIGN: Retrospective cohort study. OBJECTIVE: The aims of this study were to (1) compare patient and procedure-specific characteristics among those who had short versus long hospital stays and (2) identify independent risk factors that may correlate with extended length of hospital stay (LOS) in patients with adolescent idiopathic scoliosis (AIS) who underwent posterior segmental instrumented fusion (PSIF). SUMMARY OF BACKGROUND DATA: Reducing the LOS and identifying risk factors associated with extended admission have become increasingly relevant to healthcare policy makers. There is currently limited research identifying risk factors that correlate with extended stay in patients undergoing PSIF for AIS. METHODS: A single-institution, longitudinally maintained database was queried to identify 407 patients who met specific inclusion and exclusion criteria. Based on the distribution and median LOS in the cohort (4 days), patients were divided into those who had long versus short LOS. In both groups, patient demographics, comorbidities, preoperative scoliosis curve measurements, surgery-related characteristics, and complications were analyzed. A univariate and multivariate regression analysis was then conducted to identify independent risk factors associated with extended LOS. RESULTS: Patients who had extended LOS tended to be women (84.6% vs. 75%, P = 0.01), had more levels fused (9 ±â€Š2 vs. 7 ±â€Š2 levels, P < 0.001), had more major postoperative complications (0.8% vs. 7.4%, P = 0.002), had more blood loss during surgery (723 ±â€Š548 vs. 488 ±â€Š341 cm, P < 0.001), and received less epidural analgesia for pain control (69% vs. 89%, P < 0.001). Except for higher thoracic kyphosis, long LOS patients did not have worse preoperative radiographic curve parameters. Multivariate logistic analysis identified female sex, having ≥9 ±â€Š2 levels of fusion, operative blood loss, major postoperative complications, lack of epidural analgesia, and higher thoracic kyphosis as independent risk factors correlating for extended LOS. CONCLUSION: Independent risk factors identified by this study may be used to recognize patients with AIS at risk of prolonged hospital stay. LEVEL OF EVIDENCE: 3.

Risk factors for 90-day reoperation and readmission after lumbar surgery for lumbar spinal stenosis

OBJECTIVES: The objective of this study was to evaluate the incidence and risk factors for 90-day readmission and reoperation after elective surgery for lumbar spinal stenosis (LSS). METHODS: The authors performed a retrospective consecutive cohort analysis of patients undergoing posterior lumbar decompression with or without fusion for LSS with claudication from January 2014 through December 2015. RESULTS: Data were collected on 1592 consecutive patients. The mean age at surgery was 67.4 ± 10.1 years and 45% of patients were female. The 90-day reoperation rate was 4.7%, and 69.3% of the reoperations occurred within the first 30 days. The 90-day readmission rate was 7.2%. Multivariable analysis showed that postoperative development of a surgical site infection (SSI; odds ratio [OR] 14.09, 95% confidence interval [CI] 7.86­25.18), acute kidney injury (AKI; OR 6.76, 95% CI 2.39­19.57), and urinary tract infection (UTI; OR 3.96, 95% CI 2.43­6.37), as well as a history of congestive heart failure (CHF; OR 3.03, 95% CI 1.69­5.28), were significant risk factors for readmission within 90 days. Male sex (OR 0.60, 95% CI 0.38­0.92) was associated with decreased odds for readmission. With regards to reoperation, development of SSI (OR 25.06, 95% CI 13.54­46.51), sepsis (OR 7.63, 95% CI 1.52­40.59), UTI (OR 2.54, 95% CI 1.31­4.76), and increased length of stay (LOS; OR 1.25, 95% CI 1.17­1.33) were found to be significant risk factors. A subsequent analysis found that morbid obesity (OR 6.99), history of coronary artery disease (OR 2.263), increased duration of surgery (OR 1.004), and LOS (OR 1.07) were significant risk factors for developing an SSI. CONCLUSIONS: Overall, this study found rates of 4.7% and 7.2% for reoperation and readmission, respectively, within 90 days: 30.7% of the reoperations and 44.7% of the readmissions occurred beyond the first 30 days. A diagnosis of SSI, AKI, UTI, and history of CHF were significant factors for readmission, while male sex was associated with decreased odds for readmission. A diagnosis of SSI, sepsis, UTI, and increased LOS were found to be significant predictors for reoperation. Understanding 90-day complication rates is imperative because there has been increased discussion and healthcare policy extending the global postoperative window to 90 days. Current literature supports a readmission rate of 3%­9% after spine surgery. However, this literature either is limited to a 30-day window or does not stratify between different types of spine surgeries. ABBREVIATIONS: AKI = acute kidney injury; BPH = benign prostate hyperplasia; CAD = coronary artery disease; CHF = congestive heart failure; CI = confidence interval; CMS = Centers for Medicare and Medicaid Services; COPD = chronic obstructive pulmonary disease; DM = diabetes mellitus; EBL = estimated blood loss; LOS = length of stay; LSS = lumbar spinal stenosis; OR = odds ratio; POUR = postoperative urinary retention; SSI = surgical site infection; UTI = urinary tract infection.

Removal of Intrathecal Catheters Used in Drug Delivery Systems.

INTRODUCTION: Implanted intrathecal drug delivery systems (IDDS) are increasingly used in the treatment of spasticity and in patients with refractory pain. Literature discussing complications associated with intrathecal pump placement is widely available. However, reports of complications following the removal of chronically placed catheters are scarce. We reviewed our series of patients who had surgery to remove the intrathecal catheter. METHODS: Retrospective review was performed for all patients who underwent surgery to remove a catheter linked to an IDDS between 2010 and 2016. Patients older than 18 years were included in final analysis. Demographic (including age at removal, sex, BMI, and comorbidities) and etiologic characteristics (indications of IDDS implant and explant, interval between implant and explant, and concomitant surgery) were analyzed. Simple logistic regression was performed to seek any potential predictor of complications. RESULTS: Fifty-nine patients underwent removal of their intrathecal catheter after variable periods (mean interval of 189 months). On eight occasions, patients developed complications after catheter removal (mean interval between implant and explant was 76 months for these cases). Retained catheter was the cause of complications in half of these occasions. Persistent cerebrospinal fluid leak was the next most common complication, with requirement of an external ventricular drain and lumbar drain to facilitate wound healing on two separate occasions. CONCLUSION: Removal of an intrathecal catheter from IDDS systems may cause complications that in some cases require additional surgery.

Risk factors and associated complications for postoperative urinary retention after lumbar surgery for lumbar spinal stenosis.

BACKGROUND CONTEXT: Postoperative urinary retention (POUR) is a very common postoperative complication of all surgeries (5%-70%) that may lead to complications such as urinary tract infection (UTI), bladder overdistension, autonomic dysregulation, and increased postoperative length of stay (LOS). Within the field of spine surgery, the reported incidence rate of POUR is highly variable (5.6%-38%). Lack of clear stratification of surgical level, spinal pathology, and inadequate sample size are major limitations of available studies concerning POUR following spine surgery, which may lead to inconsistency in the incidence of POUR and the ability to model its occurrence and consequences. PURPOSE: This study examines the incidence, predictive factors, and complications of POUR in patients undergoing elective posterior lumbar decompression with or without fusion for lumbar stenosis to eliminate bias from studying procedures done in different anatomical regions and with different approaches. Additionally, this study intends to identify the consequences of POUR. STUDY DESIGN AND SETTING: A retrospective consecutive cohort analysis was performed to examine patients undergoing posterior lumbar decompression who did and did not develop POUR. PATIENT SAMPLE: All patients undergoing posterior lumbar decompression with or without fusion for lumbar stenosis with claudication from January 2014 through December 2015 at our institution were evaluated. Patients under the age of 18 and patients with spinal malignancies or infections were excluded. OUTCOME MEASURES: Physiological measures included identification of POUR by evidence of reinsertion of a Foley catheter, use of straight catheterization postoperatively, or by a clear medical diagnosis with pharmacologic treatment. Other physiological measures included identification of development of UTI, sepsis, acute kidney injury (AKI), surgical site infection (SSI), or readmission within 90 days after surgery, as well as LOS and discharge disposition. METHODS: The electronic medical record was searched for all patients meeting inclusion and exclusion criteria. Postoperative urinary retention was defined as reinsertion of a Foley catheter, use of straight catheterization postoperatively, or a clear medical diagnosis with pharmacologic treatment. Statistical analysis was performed in R statistical software package version 3.3.2. Multiple variable selection techniques were used to determine appropriate variables for regression models, and logistic models were fit to the development of POUR and postoperative complications, whereas a linear regression model was used for LOS. RESULTS: Data were collected on 1,592 consecutive patients. Among the sample population, the mean age at surgery was 67 (standard deviation 10.1) and 45% of patients were women. The incidence rate of POUR was 17.1% (273/1592). Increased age (odds ratio [OR]=1.04; 95% confidence interval [CI], 1.02-1.06; p<.001), benign prostatic hyperplasia (BPH) (OR=1.92; 95% CI, 1.32-2.78); p<.001), previous AKI (OR=3.29; 95% CI, 1.11-9.29; p=.025), and previous UTI (OR=1.69; 95% CI, 1.24-2.24; p<.001) significantly increased the probability of developing POUR. Factors including increased body mass index, coronary artery disease, congestive heart failure, diabetes mellitus, chronic obstructive pulmonary disease, tobacco use, and fusion were found to be non-significant and were excluded from the model. With respect to complications, POUR was found to be associated with development of UTI (OR=4.50; 95% CI, 3.14-6.45; p<.001), sepsis (OR=4.05; 95% CI, 1.16-13.55; p=.022), increased LOS (p<.001), increased likelihood to be discharged to a skilled nursing facility (SNF) (OR of discharge to home=0.44; 95% CI, 0.32-0.62; p<.001), and increased risk of readmission within 90 days of the index surgery (OR=1.60; 95% CI, 1.11-2.26; p=.009). Development of POUR did not increase the risk of developing AKI (OR=2.45; 95% CI, 0.93-6.30; p=.063) or a SSI (OR=1.09; 95% CI, 0.56-2.02; p=.79). CONCLUSIONS: Overall, POUR was a significant risk factor for the development of UTI, sepsis, increased LOS, discharge to a SNF, and readmission within 90 days. Surgeons and anesthesiologists should take preventative measures against POUR in individuals with increased age, BPH, AKI, and UTI within 90 days before surgery, as these factors were found to significantly increase the risk of POUR.