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Iliac screw versus S2 alar-iliac screw fixation in adults: a meta-analysis

Rafael De la Garza Ramos, Jonathan Nakhla, Daniel M. Sciubba, and Reza Yassari

OBJECTIVE

In a meta-analysis, the authors sought to compare outcomes after iliac screw (IS) versus S2 alar-iliac (S2AI) screw fixation in adult patients.

METHODS

A PubMed/MEDLINE database search was performed for studies comparing IS and S2AI screw fixation techniques in adults. Levels of evidence were assigned based on the North American Spine Society guidelines. Three outcomes were examined: 1) revision surgery rate secondary to mechanical failure or wound complications, 2) surgical site infection rate, and 3) screw prominence/pain. Data were pooled and outcomes compared between techniques. Absolute risk reductions (ARRs) were also calculated for outcome measures.

RESULTS

Five retrospective cohort studies (all level III evidence) were included in our analysis. A total of 323 adult patients were included—147 in the IS group (45.5%) and 176 in the S2AI group (54.5%). Overall, revision surgery due to mechanical failure or wound complications was needed in 66 of 323 patients (revision surgery rate 20.4%)—27.9% in the IS group and 14.2% in the S2AI group (13.7% ARR; p < 0.001). Four studies reported wound infections among 278 total patients, with an infection rate of 12.6% (35/278)—25.4% in the IS group and 2.6% in the S2AI group (22.8% ARR; p < 0.001). Three studies examined development of screw prominence/pain; combined, these studies reported screw prominence/pain in 21 of 215 cases (9.8%)—18.1% in the IS group and 1.8% in the S2AI group (16.3% ARR; p < 0.001).

CONCLUSIONS

S2AI screw fixation in adults has a significantly lower mechanical failure and complication rate than IS fixation based on the current best available evidence.

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Postoperative urinary retention in patients undergoing elective spinal surgery

David Altschul, Andrew Kobets, Jonathan Nakhla, Ajit Jada, Rani Nasser, Merritt D. Kinon, Reza Yassari, and John Houten

OBJECTIVE

Postoperative urinary retention (POUR) is a common problem leading to morbidity and an increased hospital stay. There are limited data regarding its baseline incidence in patients undergoing spinal surgery and the risk factors with which it may be associated. The purpose of this study was to evaluate the incidence of POUR in elective spine surgery patients and determine the factors associated with its occurrence.

METHODS

The authors retrospectively reviewed the records of patients who had undergone elective spine surgery and had been prospectively monitored for POUR during an 18-month period. Collected data included operative positioning, surgery duration, volume of intraoperative fluid, length of hospital stay, and patient characteristics such as age, sex, and medical comorbidities. Dialysis patients or those with complete urinary retention preoperatively were excluded from analysis.

RESULTS

Of the 397 patients meeting the study inclusion criteria, 35 (8.8%) developed POUR. An increased incidence of POUR was noted in those who underwent posterior lumbar surgery, those with benign prostatic hypertrophy (BPH), those with chronic constipation or prior urinary retention, and those using a patient-controlled analgesia pump postoperatively. An increased incidence of POUR was seen with a longer operative time but not with intraoperative intravenous fluid administration. A significant relationship between the female sex and POUR was noted after controlling for BPH, yet there was no association between POUR and diabetes or intraoperative instrumentation. Postoperative retention significantly prolonged the hospital stay. Three patients developed epidural hematomas necessitating operative reexploration, and while they experienced POUR, they also developed the full constellation of cauda equina syndrome.

CONCLUSIONS

Awareness of the risk factors for POUR may be useful in perioperative Foley catheter management and in identifying patients who need particular vigilance when they are due to void postprocedure. A greater understanding of POUR may also prevent longer hospital stays in select at-risk patients. Postoperative retention is rarely caused by a postoperative cauda equina syndrome due to epidural hematoma, which is also associated with saddle anesthesia, leg pain, and weakness, yet the delineation of isolated POUR from this urgent complication is necessary for optimal patient care.

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Editorial. Evidence for biomarkers in oncological spine surgery

Gabrielle Santangelo and Daniel M. Sciubba

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Magnesium and experimental vasospasm

R. Loch Macdonald, Daniel J. Curry, Yasuo Aihara, Zhen-Du Zhang, Babak S. Jahromi, and Reza Yassari

Object. Interest has developed in the use of magnesium (Mg++) as a neuroprotectant and antivasospastic agent. Magnesium may increase cerebral blood flow (CBF) and reduce the contraction of cerebral arteries caused by various stimuli. In this study the authors tested the hypothesis that a continuous intravenous infusion of Mg++ reduces cerebral vasospasm after experimental subarachnoid hemorrhage (SAH).

Methods. A dose-finding study was conducted in five monkeys (Macaca fascicularis) to determine what doses of intravenous MgSO4 elevate the cerebrospinal fluid (CSF) concentrations of Mg++ to vasoactive levels and to determine what effects these doses have on the diameters of cerebral arteries, as shown angiographically. After a standard dose of MgSO4 had been selected it was then administered in a randomized, controlled, blinded study to 10 monkeys (five animals/group) with SAH, beginning on Day 0 and continuing for 7 days, at which time angiography was repeated. A 0.086-g/kg bolus of MgSO4 followed by an infusion of 0.028 g/kg/day MgSO4 significantly elevated serum and CSF levels of Mg++ (five monkeys). Magnesium sulfate significantly elevated the serum level of total Mg++ from a control value of 0.83 ± 0.04 mmol/L to 2.42 ± 1.01 mmol/L on Day 7 and raised the CSF level from 1.3 ± 0.04 mmol/L to 1.76 ± 0.14 mmol/L. There was no angiographic evidence of any effect of MgSO4 on normal cerebral arteries. After SAH, the vasospasm in the middle cerebral artery was not significantly reduced (46 ± 8% in the MgSO4-treated group compared with 35 ± 6% in the placebo [vehicle]-treated group, p > 0.05, unpaired t-test).

Conclusions. Magnesium sulfate did not significantly reduce cerebral vasospasm after SAH in the doses tested. An investigation of SAH is warranted mainly to test whether a benefit can be achieved by neuroprotection or by augmentation of CBF by dilation of small vessels and/or collateral pathways.

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Effect of body mass index on surgical outcomes after posterior spinal fusion for adolescent idiopathic scoliosis

Rafael De la Garza Ramos, Jonathan Nakhla, Rani Nasser, Jacob F. Schulz, Taylor E. Purvis, Daniel M. Sciubba, Merritt D. Kinon, and Reza Yassari

OBJECTIVE

Obesity is an increasing public health concern in the pediatric population. The purpose of this investigation was to examine the impact of body mass index (BMI) on 30-day outcomes after posterior spinal fusion for adolescent idiopathic scoliosis (AIS).

METHODS

The American College of Surgeons National Surgical Quality Improvement Program Pediatric database (2013 and 2014) was reviewed. Patients 10–18 years of age who had undergone fusion of 7 or more spinal levels for AIS were included. Thirty-day outcomes (complications, readmissions, and reoperations) were compared based on patient BMI per age- and sex-adjusted growth charts as follows: normal weight (NW; BMI < 85th percentile), overweight (OW; BMI 85th–95th percentile), and obese (OB; BMI > 95th percentile).

RESULTS

Patients eligible for study numbered 2712 (80.1% female and 19.9% male) and had a mean age of 14.4 ± 1.8 years. Average BMI for the entire cohort was 21.9 ± 5.0 kg/m2; 2010 patients (74.1%) were classified as NW, 345 (12.7%) as OW, and 357 (13.2%) as OB. The overall complication rate was 1.3% (36/2712). For NW and OW patients, the complication rate was 0.9% in each group; for OB patients, the rate was 4.2% (p < 0.001). The 30-day readmission rate was 2.0% (55/2712) for all patients, 1.6% for NW patients, 1.2% for OW patients, and 5.0% for OB patients (p < 0.001). The 30-day reoperation rate was 1.4% (39/2712). Based on BMI, this reoperation rate corresponded to 0.9%, 1.2%, and 4.8% for NW, OW, and OB patients, respectively (p < 0.001). After controlling for patient age, number of spinal levels fused, and operative/anesthesia time on multiple logistic regression analysis, obesity remained a significant risk factor for complications (OR 4.61), readmissions (OR 3.16), and reoperations (OR 5.33; all p < 0.001).

CONCLUSIONS

Body mass index may be significantly associated with short-term outcomes after long-segment fusion procedures for AIS. Although NW and OW patients may have similar 30-day outcomes, OB patients had significantly higher wound complication, readmission, and reoperation rates and longer hospital stays than the NW patients. The findings of this study may help spine surgeons and patients in terms of preoperative risk stratification and perioperative expectations.

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Resection of spinal column tumors utilizing image-guided navigation: a multicenter analysis

Rani Nasser, Doniel Drazin, Jonathan Nakhla, Lutfi Al-Khouja, Earl Brien, Eli M. Baron, Terrence T. Kim, J. Patrick Johnson, and Reza Yassari

OBJECTIVE

The use of intraoperative stereotactic navigation has become more available in spine surgery. The authors undertook this study to assess the utility of intraoperative CT navigation in the localization of spinal lesions and as an intraoperative tool to guide resection in patients with spinal lesions.

METHODS

This was a retrospective multicenter study including 50 patients from 2 different institutions who underwent biopsy and/or resection of spinal column tumors using image-guided navigation. Of the 50 cases reviewed, 4 illustrative cases are presented. In addition, the authors provide a description of surgical technique with image guidance.

RESULTS

The patient group included 27 male patients and 23 female patients. Their average age was 61 ± 17 years (range 14–87 years). The average operative time (incision to closure) was 311 ± 188 minutes (range 62–865 minutes). The average intraoperative blood loss was 882 ± 1194 ml (range 5–7000 ml). The average length of hospitalization was 10 ± 8.9 days (range 1–36 days). The postoperative complications included 2 deaths (4.0%) and 4 radiculopathies (8%) secondary to tumor burden.

CONCLUSIONS

O-arm 3D imaging with stereotactic navigation may be used to localize lesions intraoperatively with real-time dynamic feedback of tumor resection. Stereotactic guidance may augment resection or biopsy of primary and metastatic spinal tumors. It offers reduced radiation exposure to operating room personnel and the ability to use minimally invasive approaches that limit tissue injury. In addition, acquisition of intraoperative CT scans with real-time tracking allows for precise targeting of spinal lesions with minimal dissection.

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Predictive value of six nutrition biomarkers in oncological spine surgery: a performance assessment for prediction of mortality and wound infection

Presented at the 2023 AANS/CNS Joint Section on Disorders of the Spine and Peripheral Nerves

Rafael De la Garza Ramos, Jessica Ryvlin, Mousa K. Hamad, Mitchell S. Fourman, Yaroslav Gelfand, Saikiran G. Murthy, John H. Shin, and Reza Yassari

OBJECTIVE

Assessment of nutritional status is fundamental in cancer patients. The objective of this study was to assess the predictive ability of 6 nutritional biomarkers for postoperative mortality and wound infection after metastatic spinal tumor surgery.

METHODS

A total of 139 patients who underwent oncological surgery for metastatic spine disease between April 2012 and August 2022 and had a minimum follow-up of 90 days were included. Six unique nutritional biomarkers were assessed: Prognostic Nutritional Index (PNI), Nutritional Risk Index (NRI), Controlling Nutritional Status Score (CONUT), total psoas cross-sectional area (TPA), body mass index (BMI), and body weight. Study endpoints were 90-day mortality rate, 12-month mortality rate, and wound infection. The discriminative ability of each of these markers was assessed with the c-statistic. A multivariate analysis was done for each of the biomarkers after a univariate analysis was first performed.

RESULTS

The 90-day mortality rate was 27% (37 of 139). The biomarkers and respective c-statistics were as follows: PNI (0.74), NRI (0.75), CONUT (0.71), TPA (0.64), BMI (0.59), and body weight (0.60). The 12-month mortality rate was 56% (51 of 91). The biomarkers and respective c-statistics were as follows: PNI (0.72), NRI (0.73), CONUT (0.70), TPA (0.63), BMI (0.59), and body weight (0.60). The wound infection rate was 8% (11 of 139). The biomarkers and respective c-statistics were as follows: PNI (0.57), NRI (0.53), CONUT (0.55), TPA (0.57), BMI (0.48), and body weight (0.52). The PNI, NRI, and CONUT all predicted 90-day and 12-month mortality after multivariate regression analysis. No association between nutrition and wound infection was found.

CONCLUSIONS

In this study, nutritional status was associated with postoperative mortality following oncological spine surgery. Three biomarkers predicted outcome independent of variables such as performance status or primary cancer. Future validation of these metrics is needed.

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Evaluation of lymphopenia as a predictor of postoperative mortality and major complications in patients undergoing surgery for metastatic spine tumors

Jessica Ryvlin, Mousa K. Hamad, Justin Langro, Benjamin Wang, Pavan Patel, Rafael De la Garza Ramos, Saikiran G. Murthy, Yaroslav Gelfand, and Reza Yassari

OBJECTIVE

Lymphopenia is often seen in advanced metastatic disease and has been associated with poor postoperative outcomes. Limited research has been done to validate this metric in patients with spinal metastases. The objective of this study was to evaluate the capability of preoperative lymphopenia to predict 30-day mortality, overall survival (OS), and major complications in patients undergoing surgery for metastatic spine tumors.

METHODS

A total of 153 patients who underwent surgery for metastatic spine tumor between 2012 and 2022 and met the inclusion criteria were examined. Electronic medical record chart review was conducted to obtain patient demographics, comorbidities, preoperative laboratory values, survival time, and postoperative complications. Preoperative lymphopenia was defined as < 1.0 K/μL based on the institution’s laboratory cutoff value and within 30 days prior to surgery. The primary outcome was 30-day mortality. Secondary outcomes were OS up to 2 years and 30-day postoperative major complications. Outcomes were assessed with logistic regression. Survival analyses were done using the Kaplan-Meier method with log-rank test and Cox regression. Receiver operating characteristic curves were plotted to classify the predictive ability of lymphocyte count as a continuous variable on outcome measures.

RESULTS

Lymphopenia was identified in 47% of patients (72 of 153). The overall 30-day mortality rate was 9% (13 of 153). In logistic regression analysis, lymphopenia was not associated with 30-day mortality (OR 1.35, 95% CI 0.43–4.21; p = 0.609). The mean OS in this sample was 15.6 months (95% CI 13.9–17.3 months), with no significant difference between patients with lymphopenia and those with no lymphopenia (p = 0.157). Cox regression analysis did not show an association between lymphopenia and survival (HR 1.44, 95% CI 0.87–2.39; p = 0.161). The major complication rate was 26% (39 of 153). In univariable logistic regression analysis, lymphopenia was not associated with the development of a major complication (OR 1.44, 95% CI 0.70–3.00; p = 0.326). Finally, receiver operating characteristic curves generated poor discrimination between lymphocyte count and all outcomes, including 30-day mortality (area under the curve 0.600, p = 0.232).

CONCLUSIONS

This study does not support prior research that had shown an independent association between low preoperative lymphocyte level and poor postoperative outcomes following surgery for metastatic spine tumors. Although lymphopenia may be used to predict outcomes in other tumor-related surgeries, this metric may not hold a similar predictive capability in the population undergoing surgery for metastatic spine tumors. Further research into reliable prognostic tools is needed.

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Readmission after spinal epidural abscess management in urban populations: a bi-institutional study

Presented at the 2019 AANS/CNS Joint Section on Disorders of the Spine and Peripheral Nerves

Michael Longo, Zach Pennington, Yaroslav Gelfand, Rafael De la Garza Ramos, Murray Echt, A. Karim Ahmed, Vijay Yanamadala, Daniel M. Sciubba, and Reza Yassari

OBJECTIVE

The incidence of spinal epidural abscess (SEA) is rising, yet there are few reports discussing readmission rates or predisposing factors for readmission after treatment. The aims of the present study were to determine the rate of 90-day readmission following medical or surgical treatment of SEA in an urban population, identify patients at increased risk for readmission, and delineate the principal causes of readmission.

METHODS

Neurosurgery records from two large urban institutions were reviewed to identify patients who were treated for SEA. Patients who died during admission or were discharged to hospice were excluded. Univariate analysis was performed using chi-square and Student t-tests to identify potential predictors of readmission. A multivariate logistic regression model, controlled for age, body mass index, sex, and institution, was used to determine significant predictors of readmission.

RESULTS

Of 103 patients with identified SEA, 97 met the inclusion criteria. Their mean age was 57.1 years, and 56 patients (57.7%) were male. The all-cause 90-day readmission rate was 37.1%. Infection (sepsis, osteomyelitis, persistent abscess, bacteremia) was the most common cause of readmission, accounting for 36.1% of all readmissions. Neither pretreatment neurological deficit (p = 0.16) nor use of surgical versus medical management (p = 0.33) was significantly associated with readmission. Multivariate analysis identified immunocompromised status (p = 0.036; OR 3.5, 95% CI 1.1–11.5) and hepatic disease (chronic hepatitis or alcohol abuse) (p = 0.033; OR 2.9, 95% CI 1.1–7.7) as positive predictors of 90-day readmission.

CONCLUSIONS

The most common indication for readmission was persistent infection. Readmission was unrelated to baseline neurological status or management strategy. However, both hepatic disease and baseline immunosuppression significantly increased the odds of 90-day readmission after SEA treatment. Patients with these conditions may require closer follow-up upon discharge to reduce overall morbidity and hospital costs associated with SEA.

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Selecting the lowest instrumented vertebra in a multilevel posterior cervical fusion across the cervicothoracic junction: a biomechanical investigation

Yaroslav Gelfand, Daniel Franco, Merritt D. Kinon, Rafael De la Garza Ramos, Reza Yassari, Jonathan A. Harris, Samantha Flamand, Joshua P. McGuckin, Jorge L. Gonzalez, Jonathan M. Mahoney, and Brandon S. Bucklen

OBJECTIVE

Posterior cervical fusion is a common surgical treatment for patients with myeloradiculopathy or regional deformity. Several studies have found increased stresses at the cervicothoracic junction (CTJ) and significantly higher revision surgery rates in multilevel cervical constructs that terminate at C7. The purpose of this study was to investigate the biomechanical effects of selecting C7 versus T1 versus T2 as the lowest instrumented vertebra (LIV) in multisegmental posterior cervicothoracic fusion procedures.

METHODS

Seven fresh-frozen cadaveric cervicothoracic spines (C2–L1) with ribs intact were tested. After analysis of the intact specimens, posterior rods and lateral mass screws were sequentially added to create the following constructs: C3–7 fixation, C3–T1 fixation, and C3–T2 fixation. In vitro flexibility tests were performed to determine the range of motion (ROM) of each group in flexion-extension (FE), lateral bending (LB), and axial rotation (AR), and to measure intradiscal pressure of the distal adjacent level (DAL).

RESULTS

In FE, selecting C7 as the LIV instead of crossing the CTJ resulted in the greatest increase in ROM (2.54°) and pressure (29.57 pound-force per square inch [psi]) at the DAL in the construct relative to the intact specimen. In LB, selecting T1 as the LIV resulted in the greatest increase in motion (0.78°) and the lowest increase in pressure (3.51 psi) at the DAL relative to intact spines. In AR, selecting T2 as the LIV resulted in the greatest increase in motion (0.20°) at the DAL, while selecting T1 as the LIV resulted in the greatest increase in pressure (8.28 psi) in constructs relative to intact specimens. Although these trends did not reach statistical significance, the observed differences were most apparent in FE, where crossing the CTJ resulted in less motion and lower intradiscal pressures at the DAL.

CONCLUSIONS

The present biomechanical cadaveric study demonstrated that a cervical posterior fixation construct with its LIV crossing the CTJ produces less stress in its distal adjacent discs compared with constructs with C7 as the LIV. Future clinical testing is necessary to determine the impact of this finding on patient outcomes.