Evaluation of prognostic risk models for postoperative pulmonary complications in adult patients undergoing major abdominal surgery: a systematic review and international external validation cohort study

BACKGROUND

Stratifying risk of postoperative pulmonary complications after major abdominal surgery allows clinicians to modify risk through targeted interventions and enhanced monitoring. In this study, we aimed to identify and validate prognostic models against a new consensus definition of postoperative pulmonary complications.

METHODS

We did a systematic review and international external validation cohort study. The systematic review was done in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. We searched MEDLINE and Embase on March 1, 2020, for articles published in English that reported on risk prediction models for postoperative pulmonary complications following abdominal surgery. External validation of existing models was done within a prospective international cohort study of adult patients (≥18 years) undergoing major abdominal surgery. Data were collected between Jan 1, 2019, and April 30, 2019, in the UK, Ireland, and Australia. Discriminative ability and prognostic accuracy summary statistics were compared between models for the 30-day postoperative pulmonary complication rate as defined by the Standardised Endpoints in Perioperative Medicine Core Outcome Measures in Perioperative and Anaesthetic Care (StEP-COMPAC). Model performance was compared using the area under the receiver operating characteristic curve (AUROCC).

FINDINGS

In total, we identified 2903 records from our literature search; of which, 2514 (86·6%) unique records were screened, 121 (4·8%) of 2514 full texts were assessed for eligibility, and 29 unique prognostic models were identified. Nine (31·0%) of 29 models had score development reported only, 19 (65·5%) had undergone internal validation, and only four (13·8%) had been externally validated. Data to validate six eligible models were collected in the international external validation cohort study. Data from 11 591 patients were available, with an overall postoperative pulmonary complication rate of 7·8% (n=903). None of the six models showed good discrimination (defined as AUROCC ≥0·70) for identifying postoperative pulmonary complications, with the Assess Respiratory Risk in Surgical Patients in Catalonia score showing the best discrimination (AUROCC 0·700 [95% CI 0·683-0·717]).

INTERPRETATION

In the pre-COVID-19 pandemic data, variability in the risk of pulmonary complications (StEP-COMPAC definition) following major abdominal surgery was poorly described by existing prognostication tools. To improve surgical safety during the COVID-19 pandemic recovery and beyond, novel risk stratification tools are required.

FUNDING

British Journal of Surgery Society.

P-146 Blastocyst morphometry and morphology predict ploidy

Study question

Are objective measurements and subjective assessments of blastocysts predictive of aneuploidy?

Summary answer

Aneuploidy was predicted equally well by lower trophectoderm cell count (objectively measured morphometry) or by a lower subjective trophectoderm grade.

What is known already

Blastocyst morphological grade has been reported to be moderately predictive of embryo ploidy. However, due to its subjective nature, morphological grade may be significantly more difficult to code into artificial intelligence algorithms when compared to objective measurements.

Study design, size, duration

This retrospective cohort study included all 1409 blastocysts that were subject to pre-implantation genetic testing (PGT) in a 30-month study period.

Participants/materials, setting, methods

Per clinic routine, embryos from oocyte were cultured to the blastocyst stage following conventional ovarian stimulation, oocyte retrieval, and intracytoplasmic sperm injection. If the patients opted for PGT, a laser was used to open the zona at the cleavage stage, trophectoderm biopsies were collected at the blastocyst stage, and biopsies were analyzed by next-generation sequencing. Inner cell mass sizes were measured by ocular micrometer and trophectoderm cells were counted in one plane of focus.

Main results and the role of chance

The mean patient age (including oocyte donors) was 31.9±6.4 years and the mean number of collected oocytes was 23.0±12.9. In multivariable logistic regression, greater patient age was the best available predictor of blastocyst aneuploidy (P < 0.0001). Along with age in the model, the observation of fewer trophectoderm cells (P = 0.0019) was also predictive of aneuploidy. Alternatively, the failure to have an A-grade trophectoderm (P = 0.0007) was also predictive of aneuploidy, also with age in the model. Neither the objectively measured inner cell mass size nor subjective inner cell mass grade were significant predictors of ploidy. Overall, objectively measured blastocyst morphometry was about equally predictive of ploidy as was subjective blastocyst grading, and area under the receiver operating characteristic curve was 0.62 for each model.

Limitations, reasons for caution

This study was retrospective, allowing the possibility of selection bias among patients and among embryos chosen for biopsy.

Wider implications of the findings

Artificial intelligence algorithms assessing embryos might benefit from the similar performance of subjective grading and objective measurements, because it is much easier to code objective measurements into the algorithms.

Trial registration number

None.

774 Paediatric Appendicitis Score (PAS): A Local Trial of a Risk Prediction Pathway

Aim

Right iliac fossa (RIF) pain remains the commonest acute general surgical presentation in children. Our centre had been an outlier compared with the national average in terms of negative appendicectomy rates. Thus, we designed and implemented a local pathway for risk stratification and management of children with RIF pain.

Method

The first phase was a retrospective analysis of all appendicectomies performed between April 2018 and March 2019, in children aged five to seventeen years old. Pre-operative inflammatory markers, clinical signs, and histology findings were analysed. Second phase involved designing a pathway utilizing Paediatric Appendicitis Score (PAS), a ten-point scoring system when assessing children with RIF pain. The final phase was a prospective analysis of appendicectomy results performed between August and November 2019, after implementing PAS pathway.

Results

92 cases were recruited in the first phase (mean age 12.3). 22 cases were analysed in the final phase after implementing PAS pathway (mean age 10.9). Our negative appendicectomy rates had reduced from 25% to 15.4%. In addition, we found that 96% of positive appendicectomies had either raised inflammatory markers (WCC or CRP), raised PAS (Score of ≥ 4), or both.

Conclusions

There is noticeable difference in our negative appendicectomy rates since the introduction of PAS pathway. A diagnosis of appendicitis in a child with normal inflammatory markers and PAS score seemed unlikely. Our goal is to continue utilizing the PAS pathway in our department in order to reduce unnecessary surgeries in children.

The Transverse Process Trajectory Technique: An Alternative for Thoracic Pedicle Screw Implantation-Radiographic and Biomechanical Analysis

BACKGROUND

This study evaluates the accuracy, biomechanical profile, and learning curve of the transverse process trajectory technique (TPT) compared to the straightforward (SF) and in-out-in (IOI) techniques. SF and IOI have been used for fixation in the thoracic spine. Although widely used, there are associated learning curves and symptomatic pedicular breaches. We have found the transverse process to be a reproducible pathway into the pedicle.

METHODS

Three surgeons with varying experience (experienced [E] with 20 years in practice, surgeon [S] with less than 10 years in practice, and senior resident trainee [T] with no experience with TPT) operated on 8 cadavers. In phase 1, each surgeon instrumented 2 cadavers, alternating between TPT and SF from T1 to T12 (n = 48 total levels). In phase 2, the E and T surgeons instrumented 1 cadaver each, alternating between TPT and IOI. Computed tomography scans were analyzed for accuracy of screw placement, defined as the percentage of placements without critical breaches. Axial pullout and derotational force testing were performed. Statistical analyses include paired t test and analysis of variance with Tukey correction.

RESULTS

Overall accuracy of screw placement was comparable between techniques (TPT: 92.7%; SF: 97.2%; IOI: 95.8%; P = .4151). Accuracy by technique did not differ for each individual surgeon (E: P = .7733; S: P = .3475; T: P = .4191) or by experience level by technique (TPT: P = .1127; FH: P = .5979; IOI: P = .5935). Pullout strength was comparable between TPT and SF (571 vs 442 N, P = .3164) but was greater for TPT versus IOI (454 vs 215 N, P = .0156). There was a trend toward improved derotational force for TPT versus SF (1.06 vs 0.93 Nm/degrees, P = .0728) but not for TPT versus IOI (1.36 vs 1.16 Nm/degrees, P = .74). Screw placement time was shortest for E and longest for T for TPT and SF and not different for IOI (TPT: P = .0349; SF: P < .0001; IOI: P = .1787) but did not vary by technique.

CONCLUSIONS

We describe the TPT, which uses the transverse process as a corridor through the pedicle. TPT is an accurate method of thoracic pedicle screw placement with potential biomechanical advantages and with acceptable learning curve characteristics.

CLINICAL RELEVANCE

This study provides the surgeon with a new trajectory for pedicle screw placement that can be used in clinical practice.

Feasibility of Single-Staged Bilateral Anterior Scoliosis Correction in Growing Patients

STUDY DESIGN

Retrospective analysis.

OBJECTIVES

The objective of this study was to analyze the feasibility of correcting double-curve scoliosis using dynamic scoliosis correction (DSC, also known as vertebral body tethering), which requires a bilateral anterior approach with deflation of both lungs. Typically, this approach falls under the exclusionary criteria for the eligibility for anterior scoliosis surgery. No data exists on the feasibility of single-staged bilateral DSC.

METHODS

A retrospective analysis was performed utilizing the data from 25 patients who underwent a bilateral anterior thoracic approach and instrumentation. Thirty-day postoperative complication rates were analyzed. A learning curve subanalysis was also performed to compare the first 12 patients to the remainder of the 13 patients, with a T-test (P ≤ .05).

RESULTS

Of the 25 patients treated, there was 1 intraoperative event: After performing lumbar DSC, the contralateral DSC was abandoned due to unexpected pleural scarring and staged selective thoracic fusion was performed. We observed 4 postoperative complications: 2 patients had recurrent pleural effusions, 1 patient was diagnosed with pneumonia, and 1 patient had a minor pulmonary embolism without cardiopulmonary consequences (after an international 24 hour flight). All patients recovered well. We observed a significant influence of learning curve on surgical time (328 vs 280 min, P = .03) and blood loss (480 vs 197 mL, P = .03).

CONCLUSION

Data suggests that bilateral, single-stage surgery for DSC is feasible albeit with an elevated complication rate that may partially attributable to the learning curve. Future research should focus on the cause of pulmonary complications and include a matched comparative analysis with traditional posterior fusion.

Carcinosarcomas of Ovary/Fallopian Tube: A Rare Entity

Introduction/Objective

Adnexal carcinosarcomas (MMMTs) are rare tumors (1–4% ovarian carcinomas) with worse prognosis than high grade serous carcinomas (HGS) at similar stage. They typically present at age 64–66, often with peritoneal involvement. They are biphasic tumors with stem cells undergoing divergent epithelial and sarcomatous differentiation. The epithelial component is usually HGS and drives progression of the tumor. The mesenchymal component can be homologous with high-grade spindled cells or heterologous with malignant cartilage, bone, muscle or fat. Metastases are mostly epithelial; metastatic sarcomatous components are unusual. We reviewed our single- institutional experience of adnexal MMMTs.

Methods

We reviewed our pathology database (2001–2019) to find all cases of adnexal MMMTs. We reviewed their histological features, histology of metastases and clinical outcomes.

Results

Our series consisted of 12 cases. Patients aged 41–82 years. The primary tumor sites were ovary (6 cases, 50%), fallopian tube (4, 33%), 1 each (8%) in paratubal region and infundibular ligament. Fallopian tube was involved in 8/12 cases (4 cases as primary MMMT, 4 cases with STIC or HGS). Epithelial component was serous (75%), endometrioid (17%) and mucinous (8%). Sarcomatous component was homologous in 5 cases (41%), heterologous in 7 cases: cartilage (33%), cartilage/muscle (8%), muscle (8%), cartilage/muscle/fat (8%). 3 cases were FIGO stage I, 9 had peritoneal metastases (8 stage III, 1 stage IV). Six cases had metastatic HGS; 3 had metastatic HGS with sarcomatous component, 2 with heterologous elements. Aberrant p53 pattern was seen in 7/12 and TP53 mutation was noted in 6/12. Ten patients received cytoreductive surgery and chemotherapy. 7 patients are alive with progression free survival ranging 6–59 months, 2 survived for 25 and 29 months, 3 are lost to follow-up.

Conclusion

Metastatic sarcomatous heterologous elements are rare in uterine carcinosarcomas and may suggest adnexal origin. They may correlate with worse outcome; in our series, 1/2 died after 29 months, the other was lost to follow-up. Fallopian tube involvement (75% of our cases) is of significance as identical TP53 mutation has been identified in a case report of ovarian carcinosarcoma with fallopian tube STIC. Also, our 2 cases of infundibular ligament and paratubal region may indicate seeding from fallopian tube. Further studies are needed to confirm the correlation.

Endobronchial ultrasound for tubercular mediastinal adenopathy and its comparison with traditional tools

SETTING: Endobronchial ultrasound (EBUS) is now the preferred tool to sample malignant mediastinal lesions. Data on its role in tubercular mediastinal adenopathy are limited.OBJECTIVE: To evaluate the efficacy of EBUS in diagnosing tubercular mediastinal lymphadenopathy and correlate the cytological and microbiological results obtained on aspirate with standard methods (radiology and the tuberculin skin test) suggesting tuberculosis (TB).DESIGN: A prospective study of 125 patients with suspected tubercular mediastinal lymphadenopathy who underwent EBUS-transbronchial needle aspiration. Only patients with a microbiologically confirmed diagnosis or unequivocal clinico-radiological response to anti-TB treatment during follow-up were included.RESULTS: A total of 122 patients showed findings suggesting TB on cytopathology (sensitivity 97.6%), 105 (84%) of whom had microbiological evidence of TB (positive smear/culture or both). Performing staining for acid-fast bacilli on slides prepared during the procedure vs. only on samples submitted in saline significantly improved the yield. Only 92 patients (73.6%) were Mantoux-positive. Cytology was more sensitive than computed tomography in picking up necrosis. Granulomas, with or without necrosis, were equally likely to be microbiologically positive. However, presence of only necrosis in a TB-endemic region invariably points towards TB diagnosis.CONCLUSIONS: EBUS was highly sensitive and specific for diagnosis of mediastinal TB and may be considered the investigation of choice for tubercular mediastinal adenopathy.

Comparative Evaluation of Two Quantitative Test Methods for Determining the Efficacy of Liquid Sporicides and Sterilants on a Hard Surface: A Precollaborative Study

Two quantitative carrier-based test methods for determining the efficacy of liquid sporicides and sterilants on a hard surface, the Standard Quantitative Carrier Test MethodASTM E 2111-00 and an adaptation of a quantitative micro-method as reported by Sagripanti and Bonifacino, were compared in this study. The methods were selected based on their desirable characteristics (e.g., well-developed protocol, previous use with spores, fully quantitative, and use of readily available equipment) for testing liquid sporicides and sterilants on a hard surface. In this paper, the Sagripanti-Bonifacino procedure is referred to as the Three Step Method (TSM). AOAC Official Method 966.04 was included in this study as a reference method. Three laboratories participated in the evaluation. Three chemical treatments were tested: (1) 3000 ppm sodium hypochlorite with pH adjusted to 7.0, (2) a hydrogen peroxide/peroxyacetic acid product, and (3) 3000 ppm sodium hypochlorite with pH unadjusted (pH of approximately 10.0). A fourth treatment, 6000 ppm sodium hypochlorite solution with pH adjusted to 7.0, was included only for Method 966.04 as a positive control (high level of efficacy). The contact time was 10 min for all chemical treatments except the 6000 ppm sodium hypochlorite treatment which was tested at 30 min. Each chemical treatment was tested 3 times using each of the methods. Only 2 of the laboratories performed the AOAC method. Method performance was assessed by the within-laboratory variance, between-laboratory variance, and total variance associated with the log reduction (LR) estimates generated by each quantitative method. The quantitative methods performed similarly, and the LR values generated by each method were not statistically different for the 3 treatments evaluated. Based on feedback from the participating laboratories, compared to the TSM, ASTM E 2111-00 was more resource demanding and required more set-up time. The logistical and resource concerns identified for ASTM E 2111-00 were largely associated with the filtration process and counting bacterial colonies on filters. Thus, the TSM was determined to be the most suitable method.

Bracing in Adolescent Idiopathic Scoliosis Trial (BrAIST): Development and Validation of a Prognostic Model in Untreated Adolescent Idiopathic Scoliosis Using the Simplified Skeletal Maturity System

STUDY DESIGN

Prognostic study and validation using prospective clinical trial data.

OBJECTIVE

To derive and validate a model predicting curve progression to ≥45° before skeletal maturity in untreated patients with adolescent idiopathic scoliosis (AIS).

SUMMARY OF BACKGROUND DATA

Studies have linked the natural history of AIS with characteristics such as sex, skeletal maturity, curve magnitude, and pattern. The Simplified Skeletal Maturity Scoring System may be of particular prognostic utility for the study of curve progression. The reliability of the system has been addressed; however, its value as a prognostic marker for the outcomes of AIS has not. The BrAIST trial followed a sample of untreated AIS patients from enrollment to skeletal maturity, providing a rare source of prospective data for prognostic modeling.

METHODS

The development sample included 115 untreated BrAIST participants. Logistic regression was used to predict curve progression to ≥45° (or surgery) before skeletal maturity. Predictors included the Cobb angle, age, sex, curve type, triradiate cartilage, and skeletal maturity stage (SMS). Internal and external validity was evaluated using jackknifed samples of the BrAIST data set and an independent cohort (n = 152). Indices of discrimination and calibration were estimated. A risk classification was created and the accuracy evaluated via the positive (PPV) and negative predictive values (NPV).

RESULTS

The final model included the SMS, Cobb angle, and curve type. The model demonstrated strong discrimination (c-statistics 0.89-0.91) and calibration in all data sets. The classification system resulted in PPVs of 0.71-0.72 and NPVs of 0.85-0.93.

CONCLUSIONS

This study provides the first rigorously validated model predicting a short-term outcome of untreated AIS. The resultant estimates can serve two important functions: 1) setting benchmarks for comparative effectiveness studies and 2) most importantly, providing clinicians and families with individual risk estimates to guide treatment decisions.

LEVEL OF EVIDENCE

Level 1, prognostic.

The Assessment of Clinically Significant Differences in Treating Spinal Deformity Using the SRS Questionnaire: What Is the Threshold of Change That Is Meaningful to Patients?

BACKGROUND

The measurement of health-related quality of life is important in spinal deformity surgery. The Scoliosis Research Society questionnaire has allowed disease-specific research in this area, and determining the minimal clinically important difference (MCID) is as important as it is elusive. We seek to further refine our estimations of clinically perceived improvements by the patient.

METHODS

We used an anchor-based approach for each domain of the SRS questionnaire to compare changes at 1 year after treatment. We set the MCID as the upper 95% boundary of the "no change" group bordering the "improvement" arm, where the patients may start to perceive their own change toward the better. We compared this with the mean change.

RESULTS

The threshold value for the MCID was 0.54 for the pain domain, 0.31 for function, 0.62 for self-image, and 0.5 for mental health. The mean changes in our group's pain and self-image exceeded their MCID.

CONCLUSIONS

Compared with our previous work, we further attempted to refine our assessment of the MCID in spinal deformity. Pain continues to show clinically significant improvement, and self-image also demonstrated mean improvement over its estimated MCID.

LEVEL OF EVIDENCE

2.

CLINICAL RELEVANCE

This result in self-image is an important addition to the MCID literature, given its lack of consistency in previous work.

Critical care usage after major gastrointestinal and liver surgery: a prospective, multicentre observational study

BACKGROUND

Patient selection for critical care admission must balance patient safety with optimal resource allocation. This study aimed to determine the relationship between critical care admission, and postoperative mortality after abdominal surgery.

METHODS

This prespecified secondary analysis of a multicentre, prospective, observational study included consecutive patients enrolled in the DISCOVER study from UK and Republic of Ireland undergoing major gastrointestinal and liver surgery between October and December 2014. The primary outcome was 30-day mortality. Multivariate logistic regression was used to explore associations between critical care admission (planned and unplanned) and mortality, and inter-centre variation in critical care admission after emergency laparotomy.

RESULTS

Of 4529 patients included, 37.8% (n=1713) underwent planned critical care admissions from theatre. Some 3.1% (n=86/2816) admitted to ward-level care subsequently underwent unplanned critical care admission. Overall 30-day mortality was 2.9% (n=133/4519), and the risk-adjusted association between 30-day mortality and critical care admission was higher in unplanned [odds ratio (OR): 8.65, 95% confidence interval (CI): 3.51-19.97) than planned admissions (OR: 2.32, 95% CI: 1.43-3.85). Some 26.7% of patients (n=1210/4529) underwent emergency laparotomies. After adjustment, 49.3% (95% CI: 46.8-51.9%, P<0.001) were predicted to have planned critical care admissions, with 7% (n=10/145) of centres outside the 95% CI.

CONCLUSIONS

After risk adjustment, no 30-day survival benefit was identified for either planned or unplanned postoperative admissions to critical care within this cohort. This likely represents appropriate admission of the highest-risk patients. Planned admissions in selected, intermediate-risk patients may present a strategy to mitigate the risk of unplanned admission. Substantial inter-centre variation exists in planned critical care admissions after emergency laparotomies.

Persistent involvement of anterior mesorectal fascia in carcinoma rectum - extended resection of rectum vs total pelvic exenteration: results from a single-centre retrospective study

AIM

Involvement of the anterior mesorectal fascia (iAMRF) after neoadjuvant treatment leads to either resection of the involved organ alone [extended resection of the rectum (ERR)] or total pelvic exenteration (TPE). The purpose of this study was to compare the rate of recurrence and survival of patients undergoing ERR or TPE for iAMRF after neoadjuvant treatment. The outcome of patients who underwent total mesorectal excision after downstaging was also compared.

METHOD

This was a retrospective study of primary rectal cancer patients.

RESULTS

Of 237 patients, 61 (21.5%) patients with nonmetastatic carcinoma rectum had iAMRF at baseline. Ten patients defaulted before completion of neoadjuvant chemoradiotherapy. After neoadjuvant chemoradiotherapy, 22 patients (43.1%) developed systemic metastases, seven patients (13.8%) were downstaged to free anterior mesorectal fascia and underwent total mesorectal excision (anterior resection/abdominoperineal resection) and the remaining 22 patients (43.1%) had persistent iAMRF. Thirteen patients with persistent iAMRF underwent ERR, whereas nine patients underwent TPE. The median duration of hospital stay in the TPE group was 13 days (10-26), whereas it was 7 days (5-21) in the ERR group. A clear circumferential resection margin, R0 resection, was achieved in all patients with TPE and ERR. After a median follow-up of 31.6 months, five patients with TPE (55.6%), four patients with ERR (30.7%) and three patients in the downstaged group (42.9%) developed systemic recurrence. None of the patients with TPE and the downstaged group developed local recurrence, whereas three patients with ERR (23.1%) developed local recurrence. Median disease-free survival was 12.3 months in the TPE group, 18.9 months in the ERR group and 10.6 months in the downstaged group, whereas mean overall survival was 36.2, 32.8 and 27.9 months, respectively.

CONCLUSION

Although there is no significant difference in the overall survival and disease-free survival, ERR is associated with a high risk of local recurrence compared to TPE and the downstaged group.

Preliminary Analysis of Factors Associated with Blood Loss in Neuromuscular Scoliosis Surgery

STUDY DESIGN

A retrospective review was conducted of 57 consecutive patients (26 female; mean age: 16.6 years) who underwent posterior or combined anterior-posterior spinal fusion for neuromuscular scoliosis (NMS) from 2006 and 2007.

OBJECTIVES

We aimed to assess which patient and surgical factors are predictive of increased blood loss and transfusion requirements during spinal fusion for NMS.

BACKGROUND

Spinal fusion surgery in patients with NMS has been associated with significant intraoperative blood loss and transfusion requirements. Specific factors predictive of greater blood loss have not been delineated; recognizing these factors will assist predicting the need for blood products and antifibrinolytics.

METHODS

Data gathered included demographic, operative (operative time, levels fused, estimated blood loss, cell saver transfused, IV fluids transfused, and units transfused), and laboratory parameters (hemoglobin, hematocrit, platelet count, prothrombin time, partial prothrombin time, and international normalized ratio). Multivariate linear regression was used to identify parameters associated with greater intraoperative blood loss and transfusion requirements.

RESULTS

Eighty-three percent of patients underwent primary surgery with mean levels fused of 13.5. Regression analysis showed a statistically significant increase in blood loss with age (p = 0.00), operative time (p = 0.00), and postoperative platelets (p = 0.016). Each year of increasing age corresponded with an increase of 50 cc of estimated blood loss (EBL). Each additional hour of operative time was associated with an additional EBL of 147.7 cc. Each additional unit of postoperative platelets was associated with an EBL decrease of 2.8 cc. Units transfused increased with age (p = 0.00): each year of increasing age corresponded with an increase of 0.04 units of blood transfused.

CONCLUSIONS

Patients with NMS remain a challenging group of patients to treat. We find that age, operative time, and postoperative platelets are predictive of increased blood loss while only age was related to greater transfused units. Our findings may predict the need for blood products and antifibrinolytic agents preoperatively in this heterogeneous population, especially as patients age.

Comparison of Stand-Alone, Transpsoas Lateral Interbody Fusion at L3-4 and Cranial vs Transforaminal Interbody Fusion at L3-4 and L4-5 for the Treatment of Lumbar Adjacent Segment Disease

Study Design

Retrospective cohort study.

Objective

To compare outcomes and complications of stand-alone minimally invasive lateral interbody fusion (LIF) vs revision posterior surgery for the treatment of lumbar adjacent segment disease.

Methods

Adults who underwent LIF or transforaminal lumbar interbody fusion (TLIF) for adjacent segment disease were compared. Exclusion criteria: >grade 1 spondylolisthesis, posterior approach after LIF, and L5/S1 surgery. Patient demographics, estimated blood loss, hospital length of stay, complications, reoperations, health-related quality of life measures, and radiographs were examined. Data were analyzed with the χ², Wilcoxon signed rank, and Mann-Whitney U tests.

Results

A total of 17 LIF and 16 TLIF patients were included. Demographics were similar. Follow up was similar (LIF: 22.9 ± 11.8 months vs TLIF: 22.0 ± 4.6 months; P = .86). The LIF patients had significantly less blood loss (LIF: 36 ± 16 mL vs TLIF: 700 ± 767 mL; P < .001) and shorter length of stay (LIF: 2.6 ± 2.9 days vs TLIF: 3.3 ± 0.9 days; P = .001). There were no intraoperative complications. Revision rate was 4 of 17 in LIF and 3 of 16 in TLIF (P = .73). Baseline health-related quality of life and radiographic measurements were similar. In both groups, back and leg pain scores significantly improved, and in LIF, the Owestry Disability Index, and EuroQol-5D significantly improved. The LIF had a significant increase in intervertebral height (LIF: 4.8 ± 2.9 mm, P < .001, TLIF: 1.3 ± 3.4 mm, P = .37), which was significantly greater for LIF than TLIF (P = .002). Similarly, LIF had a significant increase in segmental lordosis (LIF: 5.6° ± 4.9°, P < .001, TLIF: 3.6° ± 8.6°, P = .16), which was not significantly different between groups.

Conclusions

Patients with adjacent segment disease may receive significant benefit from stand-alone LIF or TLIF. The LIF offers advantages of less blood loss and a shorter hospital stay.

Level of Evidence

3.

Congenital anterior shoulder dislocation in a newborn treated with closed reduction

Case: This rare case presents an isolated congenital shoulder dislocation in a twin delivery, without traumatic delivery. Delivered by emergent cesarean section at 33 weeks gestation, the infant presented with a lateral shoulder crease with x-rays showing anterior and inferior dislocation. Treatment included prompt reduction and stabilization, with follow-up ultrasound demonstrating a physeal injury.

Conclusions: This case report presents the only published congenital shoulder dislocation in an infant after an atraumatic twin cesarean delivery. Prompt reduction, stabilization, and ultrasound imaging to assess for physeal injury is our recommended management for this scenario.

Proximal Junctional Kyphosis Prevention Strategies: A Video Technique Guide

BACKGROUND

Proximal junctional kyphosis (PJK) is a well-recognized complication in patients undergoing posterior instrumented fusion procedures for adult spinal deformity. Strategies that reduce rates of PJK have the potential to improve the safety of these operations and decrease cost by eliminating the need for revision surgery.

OBJECTIVE

To present a set of surgical techniques that can decrease rates of PJK in adults undergoing surgery for spinal deformity.

METHODS

We summarize the use of vertebroplasty, transverse process hooks, terminal rod contouring, and ligament augmentation as means to reduce rates of PJK.

RESULTS

We present PJK prevention strategies and a video technique guide that are safe, technically feasible, and add minimal operative time to these surgical procedures. When applied to appropriate high-risk patients, these techniques have the potential to dramatically reduce rates of PJK, which improves quality of life and decreases the cost associated with this treating adult spinal deformity.

CONCLUSION

PJK prevention strategies represent a critical area for improvement in surgery for adult spinal deformity. We present a summary of techniques that are safe, feasible, and add minimal time to the overall procedure. These techniques warrant investigation in a thoughtful, prospective manner, but are supported by existing data and compelling biomechanical rationale. Our hope is that these strategies can be applied, particularly in high-risk patients, to help reduce rates of PJK.

Global Spinal Alignment in Cervical Kyphotic Deformity: The Importance of Head Position and Thoracolumbar Alignment in the Compensatory Mechanism

BACKGROUND

Previous studies have evaluated cervical kyphosis (C-kypho) using cervical curvature or chin-brow vertical angle, but the relationship between C-kypho and global spinal alignment is currently unknown.

OBJECTIVE

To elucidate global spinal alignment and compensatory mechanisms in primary symptomatic C-kypho using full-spine radiography.

METHODS

In this retrospective multicenter study, symptomatic primary C-kypho patients (Cerv group; n = 103) and adult thoracolumbar deformity patients (TL group; n = 119) were compared. We subanalyzed Cerv subgroups according to sagittal vertical axis (SVA) values of C7 (SVAC7 positive or negative [C7P or C7N]). Various Cobb angles (°) and SVAs (mm) were evaluated.

RESULTS

SVAC7 values were –20.2 and 63.6 mm in the Cerv group and TL group, respectively (P &lt; .0001). Various statistically significant compensatory curvatures were observed in the Cerv group, namely larger lumbar lordosis (LL) and thoracic kyphosis. The C7N group had significantly lower SVACOG (center of gravity of the head) and SVAC7 (32.9 and –49.5 mm) values than the C7P group (115.9 and 45.1 mm). Sagittal curvatures were also different in T4-12, T10-L2, LL4-S, and LL. The value of pelvic incidence (PI)-LL was different (C7N vs C7P; –2.2° vs 9.9°; P &lt; .0003). Compensatory sagittal curvatures were associated with potential for shifting of SVAC7 posteriorly to adjust head position. PI-LL affected these compensatory mechanisms.

CONCLUSION

Compensation in symptomatic primary C-kypho was via posterior shifting of SVAC7, small T1 slope, and large LL. However, even in C-kypho patients, lumbar degeneration might affect global spinal alignment. Thus, global spinal alignment with cervical kyphosis is characterized as head balanced or trunk balanced.

Pre-Operative Autologous Blood Donation Does Not Affect Pre-Incision Hematocrit in Adolescent Idiopathic Scoliosis Patients. A Retrospective Cohort of a Prospective Randomized Trial

BACKGROUND

Pre-donation of autologous blood prior to spine fusion for adolescent idiopathic scoliosis (AIS) has been used in deformity surgery. The effect of pre-donation on pre-operative hematocrit (Hct) remains debated. Multiple factors may influence pre-operative Hct including intravascular volume status, patient factors, and timing of pre-operative blood donation. The purpose of this study was to determine if pre-donation significantly lowers pre-incision Hct in AIS patients.

METHODS

A retrospective cohort study of a Level-1 prospective randomized trial was conducted. 125 patients from the homogeneous population were included. AIS patients undergoing a posterior only spinal fusion for AIS were separated into two groups based on their pre-operative blood donation history. Demographic variables, pre-incision Hct, and transfusion rates were compared between the two groups using the Student's T-test.

RESULTS

Pre-donation and non pre-donation groups had 28 and 97 patients, respectively. Pre-donation group was 75% female (21F, 7M) and non pre-donation group was 78% female (76F, 21M). There was no difference between pre-donation and non pre-donation groups in mean age (15.6 ± 2.2 vs 14.8 ± 2.2, p = 0.081), BMI (23.1 ± 4.2 vs 21.7 ± 5.3, p = 0.219), and pre-incision Hct (32.8 ± 3.4 vs 33.8 ± 3.1, p = 0.628). The overall transfusion rates were equivalent (32.1± 48.0% vs 25.8 ± 44.0%, p = 0.509), however, the rate of allogenic transfusion for the pre-donation group was significantly lower (3.6 ± 18.9% vs 25.8 ± 44.0%, p = 0.011).

CONCLUSIONS

This study supports the use of pre-donation for AIS, without a significant drop in pre-incision Hct. Patients that donate are also much less likely to be exposed to allogenic blood. There may be a surgeon bias to recommend pre-donation in patients with a larger BMI and older age. Future studies are needed from a larger population of patients including those with non-AIS pathology.

LEVEL OF EVIDENCE

Level III.

Does borazine-water behave like benzene-water? A matrix isolation infrared and ab initio study

Borazine is isoelectronic with benzene and is popularly referred to as inorganic benzene. The study of non-covalent interactions with borazine and comparison with its organic counterpart promises to show interesting similarities and differences. The motivation of the present study of the borazine-water interaction, for the first time, stems from such interesting possibilities. Hydrogen-bonded complexes of borazine and water were studied using matrix isolation infrared spectroscopy and quantum chemical calculations. Computations were performed at M06-2X and MP2 levels of theory using 6-311++G(d,p) and aug-cc-pVDZ basis sets. At both the levels of theory, the complex involving an N-H⋯O interaction, where the N-H of borazine serves as the proton donor to the oxygen of water was found to be the global minimum, in contrast to the benzene-water system, which showed an H-π interaction. The experimentally observed infrared spectra of the complexes corroborated well with our computations for the complex corresponding to the global minimum. In addition to the global minimum, our computations also located two local minima on the borazine-water potential energy surface. Of the two local minima, one corresponded to a structure where the water was the proton donor to the nitrogen of borazine, approaching the borazine ring from above the plane of the ring; a structure that resembled the global minimum in the benzene-water H-π complex. The second local minimum corresponded to an interaction of the oxygen of water with the boron of borazine, which can be termed as the boron bond. Clearly the borazine-water system presents a richer landscape than the benzene-water system.

Medicare Reimbursement for Total Joint Arthroplasty: The Driving Forces

BACKGROUND

Total joint arthroplasty is a large and growing part of the U.S. Medicare budget, drawing attention to how much providers are paid for their services. The purpose of this study was to examine the variables that affect total joint arthroplasty reimbursement. Along with standard economic variables, we include unique health-care variables. Given the focus on value in the Affordable Care Act, the model examines the relationship of the quality of care to total joint arthroplasty reimbursement. We hoped to find that reimbursement patterns reward quality and reflect standard economic principles.

METHODS

Multivariable regression was performed to identify variables that correlate with Medicare reimbursement for total joint arthroplasty. Inpatient charge or reimbursement data on Medicare reimbursements were available for 2,750 hospitals with at least 10 discharges for uncomplicated total joint arthroplasty from the Centers for Medicare & Medicaid Services (CMS) for fiscal year 2011. Reimbursement variability was examined by using the Dartmouth Atlas to group institutions into hospital referral regions and hospital service areas. Independent variables were taken from the Dartmouth Atlas, CMS, the WWAMI (Washington, Wyoming, Alaska, Montana, Idaho) Rural Health Research Center, and the United States Census.

RESULTS

There were 427,207 total joint arthroplasties identified, with a weighted mean reimbursement of $14,324.84 (range, $9,103 to $38,686). Nationally, the coefficient of variation for reimbursements was 0.19. The regression model accounted for 52.5% of reimbursement variation among providers. The total joint arthroplasty provider volume (p < 0.001) and patient satisfaction (p < 0.001) were negatively correlated with reimbursement. Government ownership of a hospital (p < 0.001) and higher Medicare costs (p < 0.001) correlated positively with reimbursement.

CONCLUSIONS

Medicare reimbursements for total joint arthroplasty are highly variable. Greater reimbursement was associated with lower patient volume, lower patient satisfaction, a healthier patient population, and government ownership of a hospital. As value-based reimbursement provisions of the Affordable Care Act are implemented, there will be dramatic changes in total joint arthroplasty reimbursements. To meet these changes, providers should expect qualities such as high patient volume, willingness to care for sicker patient populations, patient satisfaction, safe outcomes, and procedural demand to correlate with their reimbursement.

CLINICAL RELEVANCE

Practicing orthopaedic surgeons and hospital administrators should be aware of discrepancies in inpatient reimbursement for total joint arthroplasty from Medicare. Furthermore, these discrepancies are not associated with typical economic factors. These findings warrant further investigation and collaboration between policymakers and providers to develop value-based reimbursement.

A Comparison of Two Different Dosing Protocols for Tranexamic Acid in Posterior Spinal Fusion for Spinal Deformity: A Prospective, Randomized Trial

BACKGROUND

Multilevel spinal fusions have typically been associated with significant blood loss. Previous studies have shown a reduction in blood loss with antifibrinolytics in both adolescent and adult spinal deformity patients. While this has been mirrored in other subspecialties as well, the dosing of TXA remains highly variable. To date, there remains a paucity of data guiding dosing for TXA in spine surgery and orthopedic surgery as a whole.

METHODS/DESIGN

One hundred and fifty patients from 3 institutions (50 each site) will be consecutively enrolled and randomized to either a high dose of TXA (50mg/kg loading followed by 20mg/kg hourly) or a lose dose (10mg/kg, then 1mg/kg hourly). Both surgeons and patients will be blinded to the treatment group. Primary outcomes will be perioperative blood loss, drain output, and transfusion rate. Secondary outcomes will be length of stay, complications, and overall cost.

DISCUSSION

The primary goal of this study is to provide level-1 comparative data for two TXA dosing regimens in adult spinal deformity surgery. Management of blood loss remains a critical factor in reducing complications during spinal deformity surgery. The null hypothesis is that there is no difference between high- and low-dose TXA with respect to any of the primary or secondary outcomes.

Spinal metastasis of breast cancer presenting after 25 years: An extremely rare presentation

Breast cancer is the most frequently diagnosed cancer in females of the developed world and is gradually becoming the leading cause in the developing world as well. The innate biology of breast cancer is marked by varied presentations, characteristics, response, recurrence and metastatic phenomenon. Even an early stage breast cancer has the potential to recur and/or metastasize after extremely long duration and this possibility should be borne in the clinician's mind.

Spinal Dural Arteriovenous Fistula Presenting as a Recurrent Nucleus Pulposus Herniation: A Case Report and Literature Review

CASE

Of the many potential causes of nerve compression that lead to radiculopathy, vascular etiologies remain among the most infrequent, with an estimated prevalence of only five to ten per million cases of radiculopathy. In this case report, we outline the clinical presentation, imaging, intraoperative findings, and pathologic findings for a fifty-four-year old patient with an intradural, extramedullary form of a spinal dural arteriovenous fistula at the L1-L2 level who presented only with axial back pain and radiculopathy. The radiologist and surgeon initially diagnosed the patient with a herniated nucleus pulposus. However, the intraoperative findings and angiogram were suggestive of an arteriovenous fistula. Methods to identify this rare entity are described for the orthopaedic spine community.

CONCLUSION

The potential for a missed diagnosis is particularly important as many partial discectomy procedures are performed at small surgical centers with limited blood products available and no vascular surgeon on staff. For patients with preoperative magnetic resonance imaging (MRI) that is suggestive of vascular malformations (T2 hyperintensity in the lower spinal cord and conus medullaris), we recommend that MR angiography be performed as a secondary diagnostic evaluation. MR angiography has a 95% positive predictive value for specifically diagnosing an arteriovenous fistula.

Radiographic Outcomes of Postoperative Taping Following Hallux Valgus Correction

BACKGROUND

Traditionally, hallux valgus operative correction has been accompanied by serial spica taping of the great toe during the postoperative period.

METHODS

We retrospectively reviewed 187 adult patients who underwent proximal first metatarsal osteotomy with a modified McBride procedure in 2008-2009 (n = 83) and 2011-2012 (n = 104). Postoperatively, to maintain the corrected position of the hallux, patients from 2008 through 2009 underwent weekly spica taping, while patients from 2011 through 2012 utilized a toe separator. The hallux valgus angle (HVA) and intermetatarsal angle (IMA) were measured using anteroposterior weight-bearing preoperative, 2-week postoperative non-weight-bearing, and 3-month weight-bearing final follow-up radiographs. A mixed-effects linear regression model identified differences between the treatment groups over time, and a t test compared actual radiographic differences at final follow-up.

RESULTS

The mixed-effects model revealed no significant difference in the HVA over time when comparing patients taped to those not taped at the preoperative (33 ± 6 vs 33 ± 6), 2-week postoperative (10 ± 7 vs 9 ± 6), and 3-month follow-up (14 ± 6 vs 11 ± 7) visits (P = .08). At final follow-up, the HVA was lower for the group that was not taped, but the difference (2.5 degrees) was below the minimal clinically important difference (MCID) (P = .015, 95% CI 0.5-4.5). For IMA, there was improved maintenance of correction over time in the patients that were not taped compared to those taped at the preoperative (15 ± 3 vs 15 ± 3), 2-week postoperative (2 ± 2 vs 3 ± 3), and 3-month follow-up (5 ± 4 vs 7 ± 4) visits (P = .002). At final follow-up, the IMA was lower for the group that was not taped, but the difference (1.7 degrees) was below the MCID (P = .004, 95% CI 0.7-2.9).

CONCLUSIONS

We report no radiographic benefit of postoperative taping after hallux valgus correction. The present study challenges the previous dogma of postoperative spica taping as the protocol is cost and time intensive for the patient and surgeon.

LEVEL OF EVIDENCE

Level III, comparative series.

Vertebral body replacement by posterior approach for metastatic disease in the thoracic spine--modified technique using an expandable cage

OBJECTIVE

To describe the technique of all-posterior vertebral body replacement using an expandable cage and angled instruments. This method facilitates implant seating with limited posterior decompression useful in the setting of metastatic disease.

INDICATIONS

Patients with metastatic disease of the thoracic spine with or without spinal cord compression.

CONTRAINDICATIONS

Patients with a limited life expectancy of less than 6 months. Multiple foci of metastatic disease in the spine.

SURGICAL TECHNIQUE

A hemilaminectomy was performed followed by nerve root sacrifice. The pleura was mobilized away from the vertebral body, after which decompression and tumor resection was performed from an all-posterior approach. An expandable vertebral body cage was inserted with a rotational manoeuvre and expanded in situ.

POSTOPERATIVE MANAGEMENT

The patient was mobilized on postoperative day 1. A chest X-ray is also recommended to exclude incidental pneumothorax.

RESULTS

Four patients were operated by an all-posterior vertebral body replacement during a 6-month period. The average length of surgical procedure was 187 min (range 165-220 min). No patient required a transthoracic approach. There were no intra- or postoperative complications and all patients could be discharged to home self-ambulating.

The relative efficacy of antifibrinolytics in adolescent idiopathic scoliosis: a prospective randomized trial

BACKGROUND

Antifibrinolytics can reduce intraoperative blood loss. The primary aim of this study was to determine the efficacy of intraoperative tranexamic acid, epsilon-aminocaproic acid, and placebo at reducing perioperative blood loss and the transfusion rate in patients with adolescent idiopathic scoliosis undergoing posterior spinal arthrodesis.

METHODS

This is a prospective, randomized, double-blind comparison of tranexamic acid, epsilon-aminocaproic acid, and placebo used intraoperatively in patients with adolescent idiopathic scoliosis. One hundred and twenty-five patients with adolescent idiopathic scoliosis were randomly assigned to the tranexamic acid, epsilon-aminocaproic acid, or control groups. Parameters recorded included estimated blood loss, hematocrit, blood product usage, drain output, and total blood losses. The primary outcomes were intraoperative blood loss and postoperative drainage. Secondary outcomes were transfusion requirements and hematocrit changes both intraoperatively and postoperatively.

RESULTS

One hundred and twenty-five patients (ninety-seven female and twenty-eight male, with a mean age of fifteen years) were randomized to receive tranexamic acid (thirty-six patients), epsilon-aminocaproic acid (forty-two patients), or saline solution (forty-seven patients). The groups were similar at baseline, with one exception: the saline solution group had a higher estimated blood volume at baseline than the tranexamic acid group. Both tranexamic acid and epsilon-aminocaproic acid reduced the estimated blood loss per degree and estimated blood loss per pedicle screw. Epsilon-aminocaproic acid, but not tranexamic acid, reduced estimated blood loss and estimated blood loss per level. Tranexamic acid also reduced total blood losses compared with epsilon-aminocaproic acid or saline solution. In an analysis controlling for level, degree, and number of anchors, tranexamic acid reduced drain output and total blood losses. Tranexamic acid or epsilon-aminocaproic acid had a smaller decrease in hematocrit postoperatively. In an analysis controlling for the mean arterial pressure during surgical exposure, tranexamic acid reduced estimated blood loss and total blood losses. Overall, antifibrinolytics (tranexamic acid or epsilon-aminocaproic acid) reduced estimated blood loss, total blood losses, and the decline in hematocrit postoperatively compared with saline solution. There was no difference among the groups with respect to the transfusion rate, duration of surgery, levels fused, or pedicle screws placed.

CONCLUSIONS

Tranexamic acid and epsilon-aminocaproic acid reduced operative blood loss but not transfusion rate. Tranexamic acid is more effective at reducing postoperative drainage and total blood losses compared with epsilon-aminocaproic acid. Maintenance of the mean arterial pressure at &lt;75 mm Hg during surgical exposure appears to be critical for maximizing antifibrinolytic benefit.

LEVEL OF EVIDENCE

Therapeutic Level I. See Instructions for Authors for a complete description of levels of evidence.

Delayed Abdominal Compartment Syndrome as a Complication of Spinal Surgery: Literature Review and Case Report

Posterior spinal fusion surgery for neuromuscular scoliosis is associated with favorable outcomes and high caregiver satisfaction scores. However, these patients represent a medically fragile patient population prone to complications. One of the more unpredictable complications is abdominal compartment syndrome (ACS), the etiology of which is not fully understood. This case report represents the first case report of delayed ACS to develop 3 days after spinal fusion in a patient with no history of previous abdominal surgeries undergoing correction for neuromuscular scoliosis. This case outlines the clinical course, risk factors for ACS, and indications for urgent surgical decompression of the abdomen. Given the high mortality, it is important for orthopedic surgeons to understand prevention, presentation, and timely management associated with ACS.

Reduction of Mean Arterial Pressure at Incision Reduces Operative Blood Loss in Adolescent Idiopathic Scoliosis

BACKGROUND

Spinal fusion surgery for adolescent idiopathic scoliosis (AIS) has been associated with significant blood loss and transfusion requirements. Reduction of mean arterial pressure (MAP) has benefits, but has been debated. This study aimed to analyze hypotensive anesthesia (MAP less than 65 mm Hg) at incision for its effect on blood loss.

METHODS

Retrospective analysis of 327 AIS patients treated by a single surgeon from 2000 to 2008. We recorded demographic, laboratory, and radiographic measurements and perioperative data, including complications. We estimated MAP from the anesthesia flow sheet at incision (I-MAP) and during the entire surgery (Avg MAP). Patients were stratified into 3 groups: low (MAP less than 65), medium (MAP 65-75), or high (MAP greater than 75). We also evaluated the effect of elevated blood pressure at incision. The groups were as follows: reduced (I-MAP less than Avg MAP), stable (I-MAP = Avg MAP), or elevated (I-MAP greater than Avg MAP). We performed comparisons using analysis of variance with Tukey's Multiple Comparison Test. Blood loss was recorded as absolute volume and percent total blood volume (%EBV).

RESULTS

Of the 327 patients (mean age, 15 years; range, 10-21 years; 248 females), 129 received blood transfusions (29% allogenic). There was a reduction in blood loss comparing low (584 mL; 14% EBV) versus high I-MAP (871 mL; 20.3% EBV) (p = .03). Likewise, an elevated blood pressure at incision led to increased blood loss: reduced, 510 mL, 11.5% EBV; stable, 735 mL, 17.6% EBV; and elevated, 1,033 mL, 24.9% EBV (p = .000-.02). Operative time was decreased in the low group by up to 48 minutes (p = .002), as was blood loss per minute (2.6 mL/min vs. 3.8 mL/min). There were no complications related to the use of hypotension.

CONCLUSIONS

Induction of hypotensive anesthesia (MAP less than 65 mm Hg) at incision reduces operative blood loss by 33%. In addition, elevations in blood pressure at incision increase blood loss by 29%, and operative time by 29 minutes.