Anterior Lumbar Spine Surgery Research Articles

An updated classification of the anatomical variations of the internal iliac venous drainage system: Surgical implications for anterior lumbar spinal approaches

BackgroundAdvanced pelvic surgery is associated with potential vascular risks. The aim of this study was to complete the existing classification of the anatomical variations of the internal iliac veins encountered on a series of preoperative angio CT with a view to performing anterior lumbar spine surgery. Materials and MethodsIn this monocentric retrospective study conducted between 2010 and 2020, all preoperative angio CT performed before an anterior lumbar surgery were systematically analyzed. All the abnormalities of the iliac veins were referenced in an updated classification system. Results910 patients (431 men and 479 women) with a mean age of 49 years [16–88] were included. Apart from the most common variant in the population (type I), 64 anatomical variations (7.0%) in the iliac veins were reported and classified according to our new classification. The percentage of coverage of the L4-L5 intervertebral disc is 52%, including 32% by the inferior vena cava before the confluence of the common iliac veins. At the level of the L5-S1 intervertebral disc, the coverage is 30% (same distribution between left and right). ConclusionsVariations of the iliac veins are frequent, and contrary to what one might think, and even if they can represent an anatomical trap during surgery, certain variations do not limit anterior lumbar spine surgery and are not more associated with vascular complications. Nevertheless, these anatomical variations must be known before any advanced pelvic surgery. Depending on their distribution, level L5-S1 is more suitable for ALIF, level L4-L5 for OLIF approaches.

Is the Use of Intraoperative Neuromonitoring Justified During Lumbar Anterior Approach Surgery?

Intraoperative neuromonitoring (IONM) became widely used in spine surgery to reduce the risk of iatrogenic nerve injury. However, the proliferation of IONM has fallen into question based on effectiveness and costs, with a lack of evidence supporting its benefit for specific spine surgery procedures. The purpose of this study was to evaluate the use of IONM and the rate of neurological injury associated with anterior lumbar spinal surgery. This was a retrospective study on a consecutive series of 359 patients undergoing lumbar anterior approach surgery for anterior lumbar interbody fusion (ALIF), total disc replacement (TDR), or hybrid (ALIF with TDR) for the treatment of symptomatic disc degeneration. Patients undergoing any posterior spine surgery were excluded. Operative notes were reviewed to identify any changes in IONM and the surgeon's response. Clinic notes were reviewed up to 3 months postoperatively for indications of iatrogenic nerve injury. There were 3 aberrant results with respect to IONM. Changes in IONM of a lower extremity occurred for 1 patient (0.3%). The surgeon evaluated the situation and there was no observable reason for the IONM change. Upon waking, the patient was found to have no neurological deficit. There were 2 cases of neurologic deficits in this population, which were classified as false-negatives of IONM (0.56%, 95% CI: 0.1% to 1.8%). In both cases, the patients were found to have a foot drop after the anterior approach surgery. In this study, there was 1 false-positive and 2 false-negative results of IONM. These data suggest that IONM is not beneficial in this population. However, many surgeons may feel obligated to use IONM for medicolegal reasons. There is a need for future studies to delineate cases in which IONM is beneficial and the type of monitoring to use, if any, for specific spine surgery types. This study questions the routine use of IONM in anterior lumbar approach surgery for the treatment of symptomatic disc degeneration. This has significant implications related to the cost of this practice.

Comparison of standard and modified prone positioning for lateral lumbar spine fusion: a feasibility study to reduce lumbar plexus injury.

Single-prone-lateral (PL) positioning is a new technique that allows for simultaneous anterior and posterior lumbar spine surgery. However, there is a concern regarding the risk of lumbar plexus injury in PL positioning. This study compared the risk of lumbar plexus damage and the overall safety profile of a modified PL (mPL) position to the standard PL (sPL) position for lateral lumbar spine fusion surgery. A crossover soft cadaveric study was conducted with two raters examining the comparative outcomes of position A: sPL and position B: mPL. The mPL position differs from the sPL position in that the ipsilateral arm is placed at the side of the body rather than above the head. To assess positive results (no lumbar plexus injury) between positions A and B, a mixed effects logistic regression model was utilized. The odds ratio of a good result between positions B and A was also determined. The odds ratio of the favorable outcome between position B and A was 1.77, indicating significantly higher odds of a favorable outcome in the modified position B than in the control or position A. The mPL positioning outperformed the sPL positioning in terms of safety and efficacy for lateral lumbar spine fusion. The mPL positioning may reduce the risk of lumbar plexus injury by allowing for a more direct approach to the lumbar spine and by avoiding excessive stretching of the lumbar plexus.

Clinical Application of Microscope-Assisted Minimally Invasive Anterior Lumbar Interbody Fusion

This study aims to investigate the technical aspects of microscope-assisted anterior decompression fusion and to introduce a spreader system suitable for minimally invasive anterior lumbar interbody fusion (Mini-ALIF). This article is a technical description of anterior lumbar spine surgery under a microscope. We retrospectively collected information on patients who underwent microscope-assisted Mini-ALIF surgery at our hospital between July 2020 and August 2022. A repeated-measures ANOVA was used to compare imaging indicators between periods. Forty-two patients were included in the study. The mean volume of intraoperative bleeding was 180 mL, and the mean operative time was 143 min. The mean follow-up time was 18 months. Apart from one case of peritoneal rupture, no other serious complications occurred. The postoperative foramen and disc height were both higher on average than before surgery. The spreader-assisted micro-Mini-ALIF is simple and easy to use. It can provide good intraoperative disc exposure, good discrimination of important structures, adequate spreading of the intervertebral space, and the restoration of the necessary intervertebral height, which is very helpful for less experienced surgeons.

Pneumocephalus After Anterior Lumbar Spinal Surgery Due to Trauma: A Case Report

Pneumocephalus as a complication of anterior lumbar spinal surgery is extremely rare. A 53-year-old male patient presented with L4 fracture. Posterior fixation from L3 to L5 was conducted one day after the trauma. As the patient’s neurological deficit persisted, additional anterior surgery by L4 vertebral body replacement was performed on the 19th day. Both surgeries were completed without obvious intraoperative complications. Two weeks after the anterior lumbar surgery, the patient complained of severe headaches, and computed tomography scan revealed pneumocephalus and massive fluid retention in the abdomen. The symptoms improved with conservative treatment, including bed rest, spinal drainage, intravenous drip infusion, and prophylactic administration of antibiotics. Due to the lack of tamponade effect in the soft tissues, a large amount of cerebrospinal fluid leakage may induce and cause progression of pneumocephalus in anterior dural injury.

Anterior Longitudinal Ligament Flap Technique: Description of Anterior Longitudinal Ligament Opening During Anterior Lumbar Spine Surgery and Review of Vascular Complications in 189 Patients

One of the main concerns of anterior lumbar spine approaches are vascular complications. The aim of our study is to provide technical details about a flap technique using the anterior longitudinal ligament (ALL) when approaching the lumbar spine via an anterior corridor. This can help decrease complications by protecting the adjacent vascular structures. We also include a retrospective cohort review. This is a retrospective bicentric study: 189 patients with a mean age of 44.2 years underwent anterior lumbar spine surgery using the ALL flap technique. Patients were diagnosed with degenerative pathologies. We treated 239 lumbar levels primarily at the L4-5 and L5-S1: 88 single-level anterior lumbar interbody fusions, 9 two-level ALIFs, 51 total disk replacements (TDR), and 41 hybrid constructs (i.e., ALIF L5S1 and TDR L4L5). Anterior approaches were performed by two senior spine surgeons. The ALL flap technique was utilized in all of these cases, by carefully dissecting the ALL, with the flap suspended using sutures. As such, this ALL flap provided a "safe corridor" to avoid any potential vascular laceration. The operative and early surgical complication rate was 3.2%. There was no arterial injury. There were only 2 minor venous lacerations (1.05%). No blood transfusion was required. Neither lacerations happened during disk space preparation. Here, we provide technical details about a simple and reproducible technique using the ALL as a flap, which may help spine surgeons minimize vascular injuries during ALIF or even TDR surgeries.

Outpatient Versus Inpatient Anterior Lumbar Spine Surgery: A Multisite, Comparative Analysis of Patient Safety Measures.

The frequency and complexity of spinal surgery performed in an ambulatory surgery center (ASC) is increasing. However, safety and efficacy data of most spinal procedures adapted to the ASC are sparse and have focused on anterior cervical surgery. The purpose of this study was to compare the 90-day complication and readmission rates of anterior lumbar spine surgery performed in an ASC or inpatient setting. We performed a retrospective comparative analysis of 226 consecutive anterior lumbar surgeries (283 levels treated) completed in an ASC (n = 124) or in an inpatient tertiary care hospital (n = 102) over a 3-year period. These included anterior lumbar interbody fusion (ALIF), artificial disc replacement (ADR), and hybrids. Patients undergoing simultaneous or staged posterior procedures within 3 months were excluded. Patient demographics and surgical parameters between the two surgical settings were compared. Ninety-day medical complications and readmission rates were assessed. One-way analysis of variance and Chi-square analysis were used. A P value of less than .05 was considered statistically significant. The two study groups had similar baseline characteristics. While there was a trend toward fewer complications, reoperations, and readmissions for the ASC cohort, the differences were not statistically significant. There were 7 intraoperative complications (5.6% minor vascular injury) in the inpatient cohort and 0 in the ASC cohort. The overall 90-day postoperative complication rate was 5.6% for the inpatient cohort and 0.9% for the ASC cohort. The 90-day readmission rate was 1.9% in the ASC cohort and 1.6% in the inpatient cohort. The 90-day reoperation rate was 0.8% for the inpatient cohort and 0% in the ASC cohort. The average hospital stay was 2.3 ± 1.5 days for the inpatient cohort. The 90-day readmission rates were lower for outpatients than for inpatients, while the complication and reoperation rates were similar. Our results demonstrate that anterior lumbar procedures, including single-level and multilevel ALIF, ADR, and hybrid procedures, can be performed safely in an ASC. This has significant cost savings implications for the ASC setting.

Retroperitoneoscopic debridement and internal fixation for the treatment of lumbar tuberculosis.

To describe the retroperitoneoscopic debridement technique and evaluate the clinical outcome of internal fixation for the treatment of lumbar tuberculosis.Twenty-eight patients were performed conventional laparoendoscopic technique (n = 17) or laparoendoscopic single-site technique (n = 11). Antituberculosis chemotherapy and thoracolumbosacral orthosis were given to all patients. The clinical outcomes were evaluated with preoperative and postoperative Visual Analog Scale, and radiographs with respect to sagittal angle and fusion status.Average time of the 28 procedures was 220.6 ± 50.9 min (180–365 min). The average intraoperative blood loss was 108.6 ± 95.3 mL (50–400 mL). All patients showed significant improvement of their Visual Analog Scale back pain score at follow-up and were classified as having a radiographic fusion in this study. The mean sagittal angle was 11.2 ± 3.6° before operation, significantly improved to 3.7 ± 2.4° after operation. There were no recurrent infections during the follow-up period. Complications included loosening of anterior fixation and temporary deficit of the sympathetic nerve.Retroperitoneal laparoscopic approach with CO2 insufflation technique is a challenging but safe and effective procedure for lumbar spine tuberculosis. Retroperitoneal laparoendoscopic single-site can be used for anterior lumbar spine surgery, offer exposure for L1 through L5.

Intrathecal morphine injection in anterior lumbar and lateral lumbar spine surgery: technical note.

Intrathecal morphine (ITM) is routinely used in many surgical specialties as an adjunct to postoperative analgesia. Patients undergoing lumbar spinal surgery commonly experience early postoperative pain. There have been multiple reports of the benefits of ITM in lumbar spine surgery where it has been shown to significantly reduce the need for intravenous opioid analgesia, improve time to mobilization, and shorten length of hospital stay. ITM is yet to become standard of care in Lumbar Spine Surgery likely due to concerns of it causing a cerebrospinal fluid (CSF) leak. In recent times anterior lumbar spine surgery (ALSS) and lateral lumbar spine surgery (LLSS) have increased in popularity although they are still performed in fewer numbers in comparison to the posterior [posterior lumbar interbody fusion (PLIF)] or transformational [transforaminal lumbar interbody fusion (TLIF)] approaches. Although the number of ALSS and LLSS procedures are increasing, to our knowledge there have been no reports of ITM administered via either approach reported in the literature. Herein we describe an intra-operative technique for injection of morphine into the dural sac via the Anterior and Lateral approaches to the lumbar spine. We propose that this technique can be performed easily and quickly with standard surgical equipment that is commonly available. Through use of this technique, patients undergoing spine surgery may benefit from ITM with minimal risk of iatrogenic CSF leak.

Postoperative adverse events secondary to iatrogenic vascular injury during anterior lumbar spinal surgery

Postoperative adverse events secondary to iatrogenic vascular injury during anterior lumbar spinal surgery

The usefulness and safety of the simultaneous parallel anterior and posterior combined lumbar spine surgery using intraoperative 3D fluoroscopy-based navigation (SPAPS)

BackgroundThe combined anterior-posterior surgery in the lateral decubitus position generally needs the intraoperative repositioning. However, prolonged surgical time and increased medical costs due to intraoperative repositioning have been problematic. In recent years, there have been reports of combined anterior-posterior procedure with a single position performing anterior and posterior fixation consecutively where the patient remains in the lateral decubitus position (single surgeon method-SS method). We had further advanced this method, and have adopted the Simultaneous Parallel Anterior and Posterior combined lumbar spine Surgery using intraoperative 3D fluoroscopy-based navigation (SPAPS method), where anterior and posterior procedure are performed independently by two spine surgeons. Methods66 cases that underwent SPAPS method (n=37) and SS method (n=29) from 2015 to 2019 at single institution were concluded in this study. The pre- and post-operative changes in the following were compared retrospectively between the two groups: surgical factors and clinical evaluations including JOA back pain evaluation questionnaire (JOABPEQ), visual analogue scale (VAS) on lower back pain, buttock/lower limb pain, and buttock/lower limb numbness, and Roland-Morris disability questionnaire (RDQ). ResultsThe SPAPS method was able to significantly reduce the surgical time (p=0.0025) compared to the SS method, and allowed a reduction of approximately 24.4 minutes per segment. The estimated blood loss were similar in both groups, and with regards to post-operative outcomes, both groups improved equally well. The rates of screw deviation and fusion were also similar. ConclusionsIn the case of performing the combined anterior-posterior surgery under a single position, the anterior and posterior procedure can be performed independently and simultaneously by two spine surgeons by utilizing the 3D fluoroscopy-based navigation. The surgical time can be significantly reduced by approximately 24.4 minutes per segment comparing to the SS method.

Postoperative adverse events secondary to iatrogenic vascular injury during anterior lumbar spinal surgery

Anterior lumbar spine surgery (ALSS) requires mobilization of the great vessels, resulting in a high risk of iatrogenic vascular injury (VI). It remains unclear whether VI is associated with increased risk of postoperative complications and other related adverse outcomes. The purpose of this study was to (1) assess the incidence of postoperative complications attributable to VI during ALSS, and (2) outcomes secondary to VI such as procedural blood loss, transfusion of blood products, length of stay (LOS), and in hospital mortality. Retrospective propensity-score matched, case-control study at 2 academic and 3 community medical centers, PATIENT SAMPLE: Patients 18 years of age or older, undergoing ALSS between January 1st, 2000 and July 31st, 2019 were included in this analysis. The primary outcome was the incidence of postoperative complications attributable to VI, such as venous thromboembolism, compartment syndrome, transfusion reaction, limb ischemia, and reoperations. The secondary outcomes included estimated operative blood loss (milliliter), transfused blood products, LOS (days), and in-hospital mortality. In total, 1,035 patients were identified, of which 75 (7.2%) had a VI. For comparative analyses, the 75 VI patients were paired with 75 comparable non-VI patients by propensity-score matching. The adequacy of the matching was assessed by testing the standardized mean differences (SMD) between VI and non-VI group (>0.25 SMD). Two patients (2.7%) had VI-related postoperative complications in the studied period, which consisted of two deep venous thromboembolisms (DVTs) occurring on day 3 and 7 postoperatively. Both DVTs were located in the distal left common iliac vein (CIV). The VI these patients suffered were to the distal inferior vena cava and the left CIV, respectively. Both patients did not develop additional complications in consequence of their DVTs, however, did require systemic anticoagulation and placement of an inferior vena cava filter. There was no statistical difference with the non-VI group where no instances (0%) of postoperative complications were reported (p=.157). No differences were found in LOS or in hospital mortality between the two groups (p=.157 and p=.999, respectively). Intraoperative blood loss and blood transfusion were both found to be higher in the VI group in comparison to the non-VI group (650 mL, interquartile range [IQR] 300-1400 vs. 150 mL, IQR 50-425, p≤.001; 0 units, IQR 0-3 vs. 0 units, IQR 0-1, p=.012, respectively). This study found a low number of serious postoperative complications related to VI in ALSS. In addition, these complications were not significantly different between the VI and matched non-VI ALSS cohort. Although not significant, the found DVT incidence of 2.7% after VI in ALSS warrants vigilance and preventive measures during the postoperative course of these patients.

Low Complication Rate of Anterior Lumbar Spine Surgery in an Ambulatory Surgery Center.

As healthcare costs rise, attempts are being made to perform an increasing proportion of spine surgery in ambulatory surgery centers (ASCs). ASCs are more efficient, both economically and functionally. There remains uncertainty regarding the safety of performing anterior lumbar procedures requiring vascular access, as little has been published on this subset of patients. This is a consecutive case series analysis of anterior lumbar spine surgeries that were performed in a free-standing ASC in a private-practice setting over a 1-year period, including anterior lumbar interbody fusion, artificial disc replacement, and hybrid procedures. The preoperative, intraoperative, and postoperative data recorded included age, gender, body mass index, tobacco use, and the presence of diabetes; level and procedure, operating room time, estimated blood loss, complications; discharge site, occurrence of reoperation, hospital admission, or any medical complication or infection over a 90-day period. Fifty-one patients underwent 63 treated levels (34 artificial disc replacement, 29 anterior lumbar interbody fusion): 40 single-level, 10 two-level, one three-level. Average age was 45 years; 27 female, 24 males. None of the patients were diabetics, three were current smokers, seven were former smokers. Average body mass index was 27 ± 4 (range 16-36). Average total anesthesia time was 100 minutes (range 57-187 minutes). Average estimated blood loss was 23 mL (range 5-250 mL). Seventy-one percent of patients were discharged directly home, 29% to an aftercare facility. In the 30-day postoperative period there were no deaths, one hospital admission for pain, and no significant medical complications or surgical site infections. In this consecutive case series artificial disc replacement or anterior lumbar interbody fusion was performed at 63 levels in 51 patients in the ASC setting with an observed major complication rate of zero and hospital unplanned admission rate of 2% (1/51). This provides some evidence that these procedures are safe to perform in the ASC setting. However, a highly experienced vascular surgeon and efficient surgical team, and strict patient selection criteria are all critical in making this possible.

23. Natural language processing for automated identification of intraoperative vascular injury in anterior lumbar spine surgery

BACKGROUND CONTEXT Intraoperative vascular injury may be an unavoidable complication of anterior lumbar spine surgery. However, vascular injury has implications for quality and safety reporting as this intraoperative complication may result in serious bleeding, thrombosis, and postoperative stricture. PURPOSE The purpose of this study was to develop natural language processing (NLP) algorithms for automated surveillance of intraoperative vascular injury from free-text notes in anterior lumbar spine surgery. STUDY DESIGN/SETTING Retrospective review of electronic health records at two academic and three community medical centers. PATIENT SAMPLE Adult patients, 18 years or age or older, undergoing anterior lumbar spine surgery OUTCOME MEASURES The primary outcome was unintended vascular injury during anterior lumbar spine surgery. METHODS The training set (n=786) consisted of patients who underwent surgery prior to December 31, 2013. The independent testing set (n=249) consisted of patients who underwent surgery after January 1, 2014. An extreme-gradient boosting supervised machine learning NLP algorithm was trained for detection of intraoperative vascular injury. Performance of this algorithm was compared to current procedural terminology (CPT) and international classification of diseases (ICD) codes. RESULTS In all, 1035 patients underwent anterior lumbar spine surgery and the rate of intraoperative vascular injury was 7.2% (n=75). On temporal validation in the independent testing set, the NLP algorithm achieved c-statistic of 0.92 in comparison to 0.64 for the CPT and ICD codes. At a threshold equal to the Youden index, the NLP algorithm identified 18 of the 21 patients (sensitivity 0.86) who had a vascular injury whereas the CPT and ICD codes identified 6 of the 21 (sensitivity 0.29) patients. At this threshold, the NLP algorithm had a specificity of 0.93, negative predictive value of 0.99, positive predictive value of 0.51, and F1-score of 0.64. CONCLUSIONS Relying on administrative procedural and diagnosis codes may underestimate the rate of unintended intraoperative vascular injury in anterior lumbar spine surgery. External and prospective validation of this NLP algorithm may improve quality and safety reporting. FDA DEVICE/DRUG STATUS This abstract does not discuss or include any applicable devices or drugs.

Withdrawal notice to The lumbar autonomic nerves in males: a few anatomical insights into anterior lumbar interbody fusion

BACKGROUND CONTEXTLumbar autonomic nerve injury is an underappreciated complication of anterior lumbar spinal surgery. A detailed description of lumbar autonomic nerve anatomy would be helpful for surgeons to minimize the risk of this complication. PURPOSEThis study was designed to investigate the anatomical characteristics of lumbar autonomic nerves and provide a better understanding of these nerves for anterior lumbar spinal surgery. STUDY DESIGNA dissection-based study of 10 embalmed male cadavers. METHODSThe lumbar autonomic nerves from 10 embalmed male cadavers were dissected in this study. The position of the lumbar sympathetic trunks was recorded. Distance between the initial sites of the lumbar splanchnic nerves (LSNs) and the corresponding lumbar vertebral inferior endplate, distance between the ipsilateral and adjacent LSNs, angles formed by the LSNs and the vertical axis were measured. This study has been supported by grants from Science and Technology Planning Project of Guangdong Province (CN) (Grant No. 2017B020210010) without potential conflict of interest-associated biases in the text of the paper. RESULTSIn this study, a total of 72 LSNs were identified in the 10 human cadavers. On average, the investigation found that the initial sites of the first, second, third, and fourth LSNs were 9 mm distal, 5 mm distal, 9 mm proximal, and 9 mm distal to the inferior endplates of the L1, L2, L3, and L4 vertebrae, respectively, with variations from 6 to 11 mm for each nerve among specimens. There was no significant difference in the angle between each lumbar splanchnic nerve and the vertical axis (H=2.461, p=.482), with an angle of approximately 50°±6°. The distance between the first and the second LSNs, the second and the third LSNs, or the third and the fourth LSNs were 24±6 mm, 22±8 mm, and 55±11 mm, respectively. The bilateral lumbar sympathetic trunks (N=57, 95%) were more likely to be located in the first third of the sagittal plane at the level of the L2/3, L3/4, and L4/5 intervertebral discs. CONCLUSIONSThe study found the same number and parallel courses of LSNs on each side, and on both the left and right side, the distance between the third and the fourth LSNs was much larger than the distance between the other two adjacent LSNs. The initial sites of 80.6% (n=58) of LSNs were superior to the inferior endplate of the L3 vertebra. Improved knowledge of lumbar autonomic nerve anatomy may be of great significance in reducing complications and improving surgical safety.

Development of machine learning and natural language processing algorithms for preoperative prediction and automated identification of intraoperative vascular injury in anterior lumbar spine surgery

BACKGROUNDIntraoperative vascular injury (VI) may be an unavoidable complication of anterior lumbar spine surgery; however, vascular injury has implications for quality and safety reporting as this intraoperative complication may result in serious bleeding, thrombosis, and postoperative stricture. PURPOSEThe purpose of this study was to (1) develop machine learning algorithms for preoperative prediction of VI and (2) develop natural language processing (NLP) algorithms for automated surveillance of intraoperative VI from free-text operative notes. PATIENT SAMPLEAdult patients, 18 years or age or older, undergoing anterior lumbar spine surgery at two academic and three community medical centers were included in this analysis. OUTCOME MEASURESThe primary outcome was unintended VI during anterior lumbar spine surgery. METHODSManual review of free-text operative notes was used to identify patients who had unintended VI. The available population was split into training and testing cohorts. Five machine learning algorithms were developed for preoperative prediction of VI. An NLP algorithm was trained for automated detection of intraoperative VI from free-text operative notes. Performance of the NLP algorithm was compared to current procedural terminology and international classification of diseases codes. RESULTSIn all, 1035 patients underwent anterior lumbar spine surgery and the rate of intraoperative VI was 7.2% (n=75). Variables used for preoperative prediction of VI were age, male sex, body mass index, diabetes, L4-L5 exposure, and surgery for infection (discitis, osteomyelitis). The best performing machine learning algorithm achieved c-statistic of 0.73 for preoperative prediction of VI (https://sorg-apps.shinyapps.io/lumbar_vascular_injury/). For automated detection of intraoperative VI from free-text notes, the NLP algorithm achieved c-statistic of 0.92. The NLP algorithm identified 18 of the 21 patients (sensitivity 0.86) who had a VI whereas current procedural terminologyand international classification of diseases codes identified 6 of the 21 (sensitivity 0.29) patients. At this threshold, the NLP algorithm had a specificity of 0.93, negative predictive value of 0.99, positive predictive value of 0.51, and F1-score of 0.64. CONCLUSIONRelying on administrative procedural and diagnosis codes may underestimate the rate of unintended intraoperative VI in anterior lumbar spine surgery. External and prospective validation of the algorithms presented here may improve quality and safety reporting.

Improving blood product utilization at an ambulatory surgery center: a retrospective cohort study on 50 patients with lumbar disc replacement

BackgroundThere is minimal literature discussing anterior lumbar spine surgery in ambulatory surgery centers (ASCs). The main concern with the anterior approach to the lumbar spine is the potential for injury to great vessels. In our facility, there are two units of crossmatched blood available in addition to cell saver during the procedure. We retrospectively looked at 50 cases of lumbar total disc arthroplasty (TDA) in our ASC to determine utilization of blood products.MethodsMedical records of 50 consecutive patients who underwent a lumbar TDA at a single ASC were reviewed. Surgeries completed at the ASC were all transferred from the post anesthesia care unit to an attached convalescence care center which allows up to 3 days of observation. Patients who had either a 1 or 2 level lumbar TDA were included in the study. Data consisting of demographics, American Society of Anesthesiologist Physical Status Classification System, length of stay, estimated blood loss, cell saver volume, transfusion, perioperative and postoperative complications were recorded. Preoperative, perioperative and postoperative medical records were reviewed.ResultsMedical records of 50 consecutive patients were reviewed. The mean age was 40.86 ± 9.45. Of these, 48 (96%) had a 1-level lumbar TDA, 1(2%) had a 2-level lumbar TDA, 1 (2%) had a lumbar TDA at L4/5 and an anterior lumbar interbody fusion at L5/S1. There were no mortalities; no patient had recorded perioperative complications. No patients received allogeneic blood transfusion, 4 (8%) were re-transfused with cell saver (2 receiving approximately 400 ml and 2 receiving approximately 200 ml of re-transfused blood). All 50 (100%) were discharged home in stable condition. We had 30-day follow-up data on 35 of 50 patients. Of the 35 patients reviewed, three (8.5%) of the patients were readmitted to the hospital. One additional patient was seen in the emergency department and discharged home after negative testing. No patient was readmitted for post-operative anemia.ConclusionThe routine use of both cell saver and crossmatched blood in the operating suite for lumbar TDA may be an over-utilization of healthcare resources. In our review of 50 patients, we had no need for transfusion of allogeneic packed red blood cells (PRBCs) and only four of the 50 patients had enough blood output for re-transfusion from the cell saver. This opens the conversation for alternatives to crossmatched PRBCs being held in the operating room. Such alternatives may be the use of cell salvage, only type O blood in a cooler for each patient or keeping type O blood on constant hold in ASCs.

P77. Enhanced perioperative care decreases cost after major spinal surgery

BACKGROUND CONTEXT Enhanced recovery after surgery (ERAS) standardizes surgical care, reducing unnecessary variation. The goals are outcome improvement and secondarily cost reduction. ERAS has been applied successfully to many different surgical specialties but not yet comprehensively to spinal surgery. PURPOSE The purpose of this study is to investigate the financial effectiveness of an enhanced perioperative care pathway (EPOC) on patients undergoing elective major spinal surgery compared with patients receiving traditional perioperative care. STUDY DESIGN/SETTING Retrospective cohort comparison. PATIENT SAMPLE Patients undergoing elective major spinal surgery at a quaternary academic spine center. OUTCOME MEASURES Financial measures were direct costs B, separated into those expected not to change such as implant and supply costs, and direct costs A such as bed, nursing, pharmacy, imaging, laboratory, pathology and perioperative services. Indirect costs, noted as shared patient resources such as patient transport, environmental services, resident salaries and interpreter services, were also analyzed. Secondary outcome measures were hospital and intensive care length of stay. METHODS Consecutive adults undergoing major elective spine surgery were identified to be placed into the enhanced perioperative care pathway. Major spine surgery was identified utilizing CPT and ICD codes that represented, arthrodesis for deformity, anterior lumbar spine surgery greater than two levels or posterior lumbar greater than 3 levels, corpectomy in any area of the spine or pelvic fixation. Patients with significant medical comorbidities were also included. Two comparison groups were made. First, a historical cohort of patients from prior to EPOC implementation was identified as the TRDC or traditional care group. Second, a concurrent cohort of patients that failed to make entry into EPOC due to patients not attending preoperative sessions, scheduling conflicts or insurance authorization issues. This second group was labeled the Nopathway care or NOPC group. Briefly the EPOC pathway focused on coordination of preoperative care, patient counseling, and medical optimization before surgery. Carbohydrate loading preoperativley and nasal povidone iodine swabs were also utilized. Preoperative multi-modal analgesia was initiated with acetaminophen and gabapentin. Intraoperatively, focus on goal-directed fluid management, continuation of multi-modal analgesia with the addition of ketamine, and selective use of tranexamic acid. Postoperatively, oral intake was encouraged early, as well as early ambulation. Also ketamine, acetaminophen and gabapentin were continued post-operatively. Costs were broken into Direct A, B and indirect costs and analyzed using two-tailed t-tests. The TRDC cohort costs were adjusted for inflation. Length of stay was analyzed using student's t-test with equal variances not assumed. RESULTS A total of 620 patients had EPOC care. Among them, 183 and 129 patients received TRDC or NOPC, respectively. Total cost decreased by $19,344 after pathway in comparison to the TRDC group. Total cost decreased $5,889 comparing EPOC to a concurrent NOPC group. Direct costs B, implant and supply, were similar between NOPC and EPOC, however there was a small difference between TRDC and EPOC, possibly explained by the time difference in surgical care. There was a significant cost savings when comparing EPOC to TRDC and NOPC for other Direct costs (A) of $11,160 and $4,102, respectively. Hospital length of stay was significantly lower in EPOC than in both TRDC and NOPC. Similarly EPOC patients had significantly lower intensive care length of stay than both TRDC and NOPC. CONCLUSIONS Implementation of an ERAS strategy such as EPOC decreases cost and length of stay in patients undergoing major spine surgery. Length of stay was significantly lowered at both the intensive care and overall hospital level. The implementation of an EPOC pathway also achieved direct, indirect and total cost savings in elective major spine surgery. FDA DEVICE/DRUG STATUS Unavailable from authors at time of publication.

Successful Treatment of Internal Iliac Vein Rupture During Revisional Anterior Lumbar Spinal Surgery Using a Tack: Case Report

Successful Treatment of Internal Iliac Vein Rupture During Revisional Anterior Lumbar Spinal Surgery Using a Tack: Case Report

Successful Treatment of Internal Iliac Vein Rupture During Revisional Anterior Lumbar Spinal Surgery Using a Tack: Case Report

Successful Treatment of Internal Iliac Vein Rupture During Revisional Anterior Lumbar Spinal Surgery Using a Tack: Case Report