Evaluation of immediate postoperative complications and outcomes among military personnel treated for spinal trauma in Afghanistan: a cohort-control study of 50 cases.

STUDY DESIGN: Retrospective case-control study. OBJECTIVE: The objective of the study was to compare neurological outcomes and complication rates between a series of combat-injured patients treated in Afghanistan (AFG) and those treated at Landstuhl Regional Medical Center (LRMC). SUMMARY OF BACKGROUND DATA: At present, no studies have addressed the ideal timing and setting for surgical stabilization in combat-injured soldiers who sustain spinal trauma. METHODS: Soldiers who sustained spine injuries while deployed to Afghanistan and who underwent surgery in theater or at LRMC between 2010 and 2011 were identified. Demographic information, injury-specific data, neurological status, type of surgical intervention, postoperative complications, and need for additional surgery were abstracted for all patients. Neurological improvement was the primary dependent variable. Secondary variables included the risk of developing complications and the need for additional surgery. Statistical analysis was performed using t tests, and the Fisher exact test was used for categorical variables. RESULTS: Between 2010 and 2011, 30 individuals were treated in AFG, and 20 received surgery at LRMC. Neurological improvement occurred in 10% of AFG patients and 5% of those treated at LRMC. Complications occurred in 40% of AFG patients and in 20% of the LRMC group. Twenty-three percent of AFG patients required additional spine surgery after leaving Afghanistan. There was no statistical difference in neurological improvement between the AFG and LRMC groups (P=0.64). Soldiers who received surgery in AFG were at significantly increased risk of requiring additional procedures (P=0.03). CONCLUSIONS: Soldiers treated in theater did not have statistically higher rates of neurological improvement as compared with those treated at LRMC. Patients treated in-theater were at elevated risk for the need for additional surgery. This study is among the first to evaluate clinical outcomes after surgical intervention for war-related spinal trauma. LEVEL OF EVIDENCE: Level III (case-control).

Biomechanical Comparison of Multilevel Stand-Alone Lumbar Lateral Interbody Fusion With Posterior Pedicle Screws: An In Vitro Study.

OBJECTIVE: Lumbar lateral interbody fusion (LLIF) allows placement of large interbody cages while preserving ligamentous structures important for stability. Multiple clinical and biomechanical studies have demonstrated the feasibility of stand-alone LLIF in single-level fusion. We sought to compare the stability of 4-level stand-alone LLIF utilizing wide (26 mm) cages with bilateral pedicle screw and rod fixation. METHODS: Eight human cadaveric specimens of L1-5 were included. Specimens were attached to a universal testing machine (MTS 30/G). Flexion, extension, and lateral bending were attained by applying a 200 N load at a rate of 2 mm/sec. Axial rotation of ± 8° of the specimen was performed at 2°/sec. Three-dimensional specimen motion was recorded using an optical motion-tracking device. Specimens were tested in 4 conditions: (1) intact, (2) bilateral pedicle screws and rods, (3) 26-mm stand-alone LLIF, (4) 26-mm LLIF with bilateral pedicle screws and rods. RESULTS: Compared to the stand-alone LLIF, bilateral pedicle screws and rods had 47% less range of motion in flexion-extension (p < 0.001), 21% less in lateral bending (p < 0.05), and 20% less in axial rotation (p = 0.1). The addition of bilateral posterior instrumentation to the stand-alone LLIF resulted in decreases of all 3 planes of motion: 61% in flexion-extension ( p < 0.001), 57% in lateral bending (p < 0.001), 22% in axial rotation (p = 0.002). CONCLUSION: Despite the biomechanical advantages associated with the lateral approach and 26 mm wide cages, stand-alone LLIF for 4-level fusion is not equivalent to pedicle screws and rods.

Delayed prosthetic seroma: a localized inflammatory response to COVID vaccination and infection?

We present a patient whom we believe developed a late abdominal mesh collection in response to COVID-19 mRNA vaccination booster and COVID-19 infection. A polypropylene mesh was placed during her right breast reconstruction operation 2 years ago where she underwent a right transverse abdominis rectus muscle (TRAM) free flap. She recovered uneventfully from this operation. This lady, though vaccinated, developed respiratory symptoms and tested positive for COVID-19 infection 3 days after her booster injection. She then noticed right-sided abdominal swelling 3 days after the onset of respiratory symptoms. She only presented 1 month later due to a 7-day history of pain at the site of abdominal swelling. A computed tomography scan confirmed the presence of a seroma, and she underwent ultrasound-guided percutaneous drainage. A COVID Antigen Rapid Test of the fluid returned positive, though the PCR swab returned negative. There have been no published reports of periprosthetic mesh seroma after COVID-19 vaccination or infection to date. We wanted to share our experience so that other surgeons may be aware of this potential presentation given the current ongoing pandemic. Level of evidence: Level V, risk/prognostic.

Characterization of ion release from a novel biomaterial, Molybdenum-47.5Rhenium, in physiologic environments.

BACKGROUND CONTEXT: Metals from spinal implants are released into surrounding tissues by various mechanisms. Metal ion release has been associated with clinical implant failure, osteolysis, and remote site accumulation with adverse events. Significant corrosion and associated metal ion release has been described with currently used spinal implant alloys. A novel metal alloy, Molybdenum-47.5Rhenium alloy (MoRe®), was approved for use in medical implants in 2019 by the FDA. PURPOSE: To evaluate the metal ion release profile of MoRe alloy after immersion in both a stable physiologic, as well as in an inflammatory environment. STUDY DESIGN: In vitro study. METHODS: The ion release profile of the MoRe alloy was comprehensively evaluated in-vitro after prolonged immersion in physiologic and inflammatory environments. Ion concentration analyses were then conducted using inductively coupled plasma-mass spectrometry (ICP-MS) methods. Comparative testing of titanium (Ti-6Al-4V) and cobalt chromium (Co-28Cr-6Mo) was also performed. RESULTS: Under baseline physiologic conditions, the MoRe alloy demonstrates very low molybdenum and rhenium ion release rates throughout the 30-day test period. During the first time interval (day 0-1), low levels of molybdenum and rhenium ions are detected (<0.3 µg/cm2 day) followed by a rapid reduction in the ion release rates to <0.05 µg/cm2 day during the second time interval (days 1-3) followed by a further reduction to very low steady-state rates <0.01 µg/cm2 day during the third time interval (days 3-7), which were maintained through 30 days. In the inflammatory condition (H2O2 solution), there was a transient increase in the release of molybdenum and rhenium ions, followed by a return to baseline ion release rates (days 2-4), with a further reduction to low steady-state rates of ∼0.01 µg/cm2 day (days 4-8). The measured molybdenum and rhenium ion release rates in both steady state (<0.01 µg/cm2 day), and inflammatory environments (0.01 µg/cm2 day) were far below the established FDA-permitted daily exposure (PDE) of 1,900 µg/cm2 day for molybdenum and 4,400 µg/cm2 day for rhenium. In contrast, titanium and cobalt chromium approached or exceeded their established PDE values in an inflammatory environment. CONCLUSIONS: The novel biomaterial MoRe demonstrated a lower metal ion release profile in both a physiologic and inflammatory environment and was well below the established PDE.  Comparative testing of the cobalt-chromium and titanium alloys found higher levels of ion release in the inflammatory environment that exceeded the PDE for cobalt and vanadium.

Late Seroma in Breast Implants: A Coronavirus Disease 2019 Phenomenon?

The coronavirus disease 2019 (COVID-19) pandemic has been challenging in all aspects of the medical field with new clinical presentations constantly arising. Plastic surgeons are not immune to this and need to be aware of their implications. There has been a recent report of late periprosthetic seroma (breast implant) as a clinical manifestation of COVID-19 infection. To our knowledge, this phenomenon has not been further reported. We present a 53-year-old immunocompromised lady who developed late seroma after COVID-19 infection. She eventually required explantation of the implant and is awaiting autologous reconstruction. It is likely that we will increasingly continue to see this phenomenon of implant complications as a result of COVID-19 infection and should be watchful, especially regarding potential immunocompromised patients.

Anterior Transpsoas Approach for Removal of Cement Leakage after Sacroplasty.

Introduction: Sacroplasty is a minimally invasive treatment option for severe pain due to sacral insufficiency fracture. Cement leakage is a known risk of sacroplasty. Despite the elevated risk to the L5 nerve root and lumbosacral trunk from cement leakage anterior to the sacral ala, there are no reports regarding surgical management of this complication. Technical Note: We describe an anterior retroperitoneal transpsoas approach to the sacral ala to remove cement leakage causing acute L5 radiculopathy in a 57-year-old gentleman who had undergone sacroplasty for sacral insufficiency fracture (Denis zone 1). The approach provides rapid and excellent visualization of the sacral ala without manipulation of the iliac vessels. Conclusions: We recommend that surgery be considered in a timely fashion, to utilize neuromonitoring, and that surgeons be aware of the considerable variability of the neurologic structures that will be encountered, which is described in this technical note.

Biomechanical Comparison of Unilateral and Bilateral Pedicle Screw Fixation after Multilevel Lumbar Lateral Interbody Fusion.

STUDY DESIGN: Human Cadaveric Biomechanical Study. OBJECTIVES: Lumbar Lateral Interbody Fusion (LLIF) utilizing a wide cage has been reported as having favorable biomechanical characteristics. We examine the biomechanical stability of unilateral pedicle screw and rod fixation after multilevel LLIF utilizing 26 mm wide cages compared to bilateral fixation. METHODS: Eight human cadaveric specimens of L1-L5 were included. Specimens were attached to a universal testing machine (MTS 30/G). Three-dimensional specimen range of motion (ROM) was recorded using an optical motion-tracking device. Specimens were tested in 3 conditions: 1) intact, 2) L1-L5 LLIF (4 levels) with unilateral rod, 3) L1-L5 LLIF with bilateral rods. RESULTS: From the intact condition, LLIF with unilateral rod decreased flexion-extension by 77%, lateral bending by 53%, and axial rotation by 26%. In LLIF with bilateral rods, flexion-extension decreased by 83%, lateral bending by 64%, and axial rotation by 34%. Comparing unilateral and bilateral fixation, LLIF with bilateral rods reduced ROM by a further 23% in flexion-extension, 25% in lateral bending, and 11% in axial rotation. The difference was statistically significant in flexion-extension and lateral bending (P < .005). CONCLUSIONS: Considerable decreases in ROM were observed after multilevel (4-level) LLIF utilizing 26 mm cages supplemented with both unilateral and bilateral pedicle screws and rods. The addition of bilateral fixation provides a 10-25% additional decrease in ROM. These results can inform surgeons of the incremental biomechanical benefit when considering unilateral or bilateral posterior fixation after multilevel LLIF.

Sacroiliac joint injections with the guidance of three-dimensional cone beam computed tomography (3D-CBCT) and fluoroscopy fusion.

BACKGROUND: We describe our diagnostic sacroiliac joint (SIJ) injection technique under the guidance of three-dimensional cone beam computed tomography (3D-CBCT) fused with real-time fluoroscopy. METHODS: A retrospective review of 17 patients (mean age 55.4 (range 40-74) years) who received a total of 23 diagnostic SIJ injections between March 2016 and November 2017 were performed. Pre- and post-procedure pain scores were reviewed from the medical records and then these findings were correlated with which patients were and were not diagnosed with SIJ pain by clinical management. The final diagnosis of SIJ-related pain was made in cases with at least 50% symptomatic improvement following SIJ-specific pain treatments. RESULTS: Some 87% (n=20/23) of injections achieved more than 50% pain relief after the diagnostic SIJ injection. The final diagnosis of the target SIJ-related pain after follow-up and management was found in 90% (n=18/20) of cases. There were two cases with positive tests diagnosed as non-SIJ pain including one with the diagnosis of femuroacetabular impingement and one with pain related to loosening of knee hardware. The sensitivity, specificity, positive predictive value, and negative predicative value of diagnostic SIJ injections were 100%, 60%, 89%, and 100%, respectively, with a 40% false-positive rate. There were no procedure-related complications. CONCLUSION: 3D-CBCT fused with real-time fluoroscopy for SIJ injection is accurate and safe.

Sarcopenia and mortality in different clinical conditions: A meta-analysis.

OBJECTIVES: Sarcopenia is recognized to be a health problem which is as serious as obesity, but its relevance to mortality is unclear. We conducted a meta-analysis of cohort studies on lean mass and mortality in populations with different health conditions. METHODS: In this study, a systematic search of PubMed, Cochrane Library and Embase was performed for cohort studies published before Dec 20, 2017 which examined the relationship between lean mass and mortality. We included studies reporting lean mass measurement by dual-energy X-ray absorptiometry, bioimpedance analysis or computed tomography, as continuous (per standard deviation [SD] decrease) or binary variables (using sarcopenia cutoffs). We excluded studies which used muscle mass surrogates, anthropometric measurement of muscle, rate of change in muscle mass, and sarcopenia defined by composite criteria. The primary study outcome was all-cause mortality. Pooled hazard ratio estimates were calculated using a random effects model. RESULTS: A total of 9602 articles were identified from the systematic search, and 188 studies with 98 468 participants from 34 countries were included in the meta-analysis. Of the 68 studies included in the present meta-analysis, the pooled HR was 1.36 and 1.74 for every SD decrease in lean mass and in people with low lean mass (cutoffs), respectively. Significant associations were also observed in elderly and all disease subgroups, irrespective of the measurement modalities. CONCLUSIONS: Lower lean mass is robustly associated with increased mortality, regardless of health conditions and lean mass measurement modalities. This meta-analysis highlighted low lean mass as a key public health issue.

The effect of different measurement modalities in the association of lean mass with mortality: A systematic review and meta-analysis.

OBJECTIVES: Lean mass is commonly measured by 3 modalities, dual energy X-ray absorptiometry (DXA), bioelectrical impedance analysis (BIA), and computerized tomography (CT). CT is considered the most accurate, while lean mass measured by DXA and BIA often consists of non-muscle compartment, and hence considered less accurate when compared with CT. It remains unclear if the association of lean mass with mortality would differ using different measurement modalities. METHODS: A systematic review and meta-analysis of lean mass and mortality was conducted. The analysis was stratified by different measurement modalities and health conditions. Pooled hazard ratios were estimated using a random effects model. RESULTS: This meta-analysis included 188 studies with 98 468 participants. Reduced lean mass measured by BIA, DXA, and CT, was associated with increased risk of mortality with a hazard ratio (HR) of 1.35 (95% CI, 1.21-1.49), 1.18 (95% CI, 1.06-1.30), and 1.44 (95% CI, 1.32-1.57), respectively. Similarly, low lean mass defined by BIA-, DXA-, and CT-measurement was associated with increased risk of mortality, with an HR of 1.81 (95% CI, 1.56-2.10), 1.44 (95% CI, 1.29-1.60), and 1.78 (95% CI, 1.64-1.93). CONCLUSIONS: Reduced and low lean mass were robustly associated with increased mortality in studies using different measurement modalities.

Systematic review and meta-analysis of lean mass and mortality: Rationale and study description.

OBJECTIVES: Muscle mass is one of the key components in defining sarcopenia and is known to be important for locomotion and body homeostasis. Lean mass is commonly used as a surrogate of muscle mass and has been shown to be associated with increased mortality. However, the relationship of lean mass with mortality may be affected by different clinical conditions, modalities used, cut-off point to define low or normal lean mass, and even types of cancer among cancer patients. Thus, we aim to perform a comprehensive meta-analysis of lean mass with mortality by considering all these factors. METHODS: Systematic search was done in PubMed, Cochrane Library and Embase for articles related to lean mass and mortality. Lean mass measured by dual X-ray absorptiometry, bioelectrical impedance analysis, and computerized tomography were included. RESULTS: The number of relevant studies has increased continuously since 2002. A total of 188 studies with 98 468 people were included in the meta-analysis. The association of lean mass with mortality was most studied in cancer patients, followed by people with renal diseases, liver diseases, elderly, people with cardiovascular disease, lung diseases, and other diseases. The meta-analysis can be further conducted in subgroups based on measurement modalities, site of measurements, definition of low lean mass adopted, and types of cancer for studies conducted in cancer patients. CONCLUSIONS: This series of meta-analysis provided insight and evidence on the relationship between lean mass and mortality in all directions, which may be useful for further study and guideline development.

Sarcopenia and mortality in cancer: A meta-analysis.

OBJECTIVES: The aim of this meta-analysis is to comprehensively evaluate the effects of lean mass on all-cause mortality across different cancer types. METHODS: This is a meta-analysis. Cohort studies on lean mass and mortality published before December 20, 2017 were obtained by systematic search on PubMed, Cochrane Library, and Embase. Inclusion criteria were cohort studies reporting lean mass measurements by dual-energy X-ray absorptiometry, bioimpedance analysis or computed tomography, and with all-cause mortality as the study outcome. Exclusion criteria were studies using muscle mass surrogates, anthropometric measurement of muscle, rate of change in muscle mass, and sarcopenia defined by composite criteria. Hazard ratios (HRs) and 95% confidence intervals (CIs) of low/reduced lean mass on cancer mortality were pooled with a random-effects model. Subgroup analysis stratifying studies according to cancer type and measurement index was performed. RESULTS: Altogether 100 studies evaluated the association between lean mass and cancer mortality. The overall pooled HR on cancer mortality was 1.41 (95% CI, 1.24 to 1.59) for every standard deviation decrease in lean mass and 1.69 (95% CI, 1.56 to 1.83) for patients with sarcopenia (binary cutoffs). Overall mortality was also significantly associated with sarcopenia in across various cancer types, except for hematopoietic, breast, ovarian and endometrial, and prostate cancer. CONCLUSIONS: The robust association of decreased lean mass with increased mortality further justified the importance of developing clinical guidelines for managing sarcopenia in cancer patients. Public health initiatives aiming at promoting awareness of muscle health in susceptible individuals are urgently needed.

Different definition of sarcopenia and mortality in cancer: A meta-analysis.

OBJECTIVES: Sarcopenia has been an emerging theme in clinical oncology. Various definitions of sarcopenia have been proposed, but their prognostic performance have yet to be evaluated and compared. The aim of this meta-analysis is to comprehensively evaluate the performance of different cutoff definitions of sarcopenia in cancer mortality prognostication. METHODS: This is a meta-analysis. Cohort studies on lean mass and mortality published before December 20, 2017 were obtained by systematic search on PubMed, Cochrane Library, and Embase. Inclusion criteria were cohort studies reporting binary lean mass categorized according to clearly defined cutoffs, and with all-cause mortality as study outcome. Studies were stratified according to the cutoff(s) used in defining low lean mass. The cutoff-specific hazard ratios (HRs) and 95% confidence intervals (CIs) of low lean mass on cancer mortality were pooled with a random-effects model and compared. RESULTS: Altogether 81 studies that studied binary lean mass were included. The pooled HRs on cancer mortality using the 3 most used definitions were: 1.74 (95% CI, 1.46-2.07) using the definition proposed by International Consensus of Cancer Cachexia, 1.45 (95% CI, 1.21-1.75) using that by Martin, and 1.58 (95% CI, 1.35-1.84) using that by Prado. The associations between sarcopenia and cancer mortality using other definitions were all statistically significant, despite different estimates were observed. CONCLUSIONS: The association of low lean mass with increased mortality was consistent across different definitions; this provides further evidence on the poorer survival in cancer patients with sarcopenia. However, further studies evaluating the performance of each definition are warranted.

The landscape of selection in 551 esophageal adenocarcinomas defines genomic biomarkers for the clinic.

Esophageal adenocarcinoma (EAC) is a poor-prognosis cancer type with rapidly rising incidence. Understanding of the genetic events driving EAC development is limited, and there are few molecular biomarkers for prognostication or therapeutics. Using a cohort of 551 genomically characterized EACs with matched RNA sequencing data, we discovered 77 EAC driver genes and 21 noncoding driver elements. We identified a mean of 4.4 driver events per tumor, which were derived more commonly from mutations than copy number alterations, and compared the prevelence of these mutations to the exome-wide mutational excess calculated using non-synonymous to synonymous mutation ratios (dN/dS). We observed mutual exclusivity or co-occurrence of events within and between several dysregulated EAC pathways, a result suggestive of strong functional relationships. Indicators of poor prognosis (SMAD4 and GATA4) were verified in independent cohorts with significant predictive value. Over 50% of EACs contained sensitizing events for CDK4 and CDK6 inhibitors, which were highly correlated with clinically relevant sensitivity in a panel of EAC cell lines and organoids.

Transforaminal Lumbar Interbody Fusion: Traditional Open Versus Minimally Invasive Techniques.

Recently, minimally invasive spine arthrodesis has gained popularity among spine surgeons. Minimally invasive techniques have advantages and disadvantages compared with traditional open techniques. Comparisons between short-term outcomes of minimally invasive transforaminal interbody fusion and open transforaminal interbody fusion in terms of estimated blood loss, postoperative pain, and hospital length of stay have been well documented and generally favor the minimally invasive technique. However, the advantages of minimally invasive transforaminal interbody fusion must be evaluated in the context of long-term results, such as patient-reported outcomes and the success of arthrodesis. Because the literature is equivocal in identifying the superior technique for successful long-term outcomes, more study is needed. Patient safety, the risk of complications, and the cost of these techniques also must be considered.

The impact of mental health on patient-reported outcomes in cervical radiculopathy or myelopathy surgery.

Optimizing functional outcomes and disability status are essential for effective surgical treatment of cervical spine disorders. Mental impairment is common among patients with cervical spine complaints; yet little is known about the impact of baseline mental status with respect to overall patient-reported outcomes. This was a retrospective analysis of patients with cervical spondylosis with myelopathy(CM) or radiculopathy(CR: cervical disc herniation, stenosis, or spondylosis without myelopathy) at 2-year follow-ups. Patients were assessed for several health-related quality of life HRQOL) measures at baseline and 24-months post-operatively: Neck Disability Index (NDI), Visual Analog Scale(VAS), Short Form-36(SF) Physical(PCS) and Mental(MCS) Components. Patients were dichotomized by MCS score: LOW-MCS(SF-MCS < 40th percentile) vs. HIGH-MCS(SF-MCS > 60th percentile). Independent and paired t-tests compared improvement in each group for HIGH-MCS and LOW-MCS cohorts. 375 patients were analyzed(65.4yrs, 67.6%F). LOW-MCS radiculopathy patients showed significant improvement in NDI, VAS Neck and Arm Pain(p < 0.05). HIGH-MCS radiculopathy patients showed greater improvement in NDI score, VAS Neck and Arm Pain, and improvement in PCS(all p < 0.05). Comparing baseline and 2-year follow-up, LOW-MCS CM patients showed significant improvement in PCS, NDI, VAS Neck and Arm Pain(p < 0.05). HIGH-MCS myelopathy patients group showed marked improvement in NDI scores, VAS Neck and Arm Pain(p < 0.05). LOW-MCS CR patients were more likely to be less satisfied 2-years post-op(p < 0.001). Postoperative CR patients with lower baseline mental status saw less improvement and significantly worse outcomes than patients with higher baseline mental status. Improving baseline mental health may improve post-operative recovery. Implementing additional screening and care can optimize functional outcomes and disability status for patients with CR.

How Effective is Physical Therapy for Common Low Back Pain Diagnoses?: A Multivariate Analysis of 4597 Patients.

STUDY DESIGN: A retrospective review. OBJECTIVE: The aim of this study is to evaluate whether the treatment of low back pain with physical therapy results in clinically significant improvements in patient-reported pain and functional outcomes. SUMMARY OF BACKGROUND DATA: Low back pain is a major cause of morbidity and disability in health care. Previous studies have found poor efficacy for surgery in the absence of specific indications. A variety of nonoperative treatments are available; however, there is scant evidence to guide the practitioner as to the efficacy of these treatments. METHODS: Four thousand five hundred ninety-seven patients who underwent physical therapy for the nonoperative treatment of low back pain were included. The primary outcome measures were pre-and post-treatment scores on the Oswestry Disability Index (ODI), Numeric Pain Rating Scale (NPRS) during activity, and NPRS during rest. Previously published thresholds for minimal clinically important difference (MCID) were used to determine the proportion of patients meeting MCID for each of our outcomes. Patients with starting values below the MCID for each variable were excluded from analysis. Logistic regression analysis was used to determine patient risk factors predictive of treatment failure. RESULTS: About 28.5% of patients met the MCID for improvement in ODI. Presence of night symptoms, obesity, and smoking were predictors of treatment failure for ODI. Fifty-nine percent of patients met the MCID for improvement in resting NPRS, with a history of venous thromboembolism, night symptoms, psychiatric disease, workers' compensation status, smoking, and obesity predictive of treatment failure. Sixty percent of patients met the MCID for improvement in activity NPRS, with night symptoms, workers' compensation status, and smoking predictive of treatment failure. CONCLUSION: We observed that a substantial percentage of the population did not meet MCID for pain and function following treatment of low back pain with physical therapy. Common risk factors for treatment failure included smoking and presence of night symptoms. LEVEL OF EVIDENCE: 4.

Impact of a Bundled Payment System on Resource Utilization During Spine Surgery.

BACKGROUND: In a bundled payment system, a single payment covers all costs associated with a single episode of care. Spine surgery may be well suited for bundled payments because of clearly defined episodes of care, but the impact on current practice has not been studied. We sought to examine how a theoretical bundled payment strategy with financial disincentives to resource utilization would impact practice patterns. METHODS: A multiple-choice survey was administered to spine surgeons describing eight clinical scenarios. Respondents were asked about their current practice, and then their practice in a hypothetical bundled payment system. Respondents could choose from multiple types of implants, bone grafts, and other resources utilized at the surgeon's discretion. RESULTS: Forty-three respondents completed the survey. Within each scenario, 24%-49% of respondents changed at least one aspect of management. The proportion of cases performed without implants was unchanged for four scenarios and increased in four by an average of 8%. Use of autologous iliac crest bone graft increased across all scenarios by an average of 18%. Use of neuromonitoring decreased in all scenarios by an average of 21%. Differences in costs were not statistically significant. CONCLUSIONS: Financial disincentives to resource utilization may result in some changes to surgeons' practices but these appear limited to items with less clear benefits to patients. Choices of implants, which account for the majority of intra-operative costs, did not change meaningfully. A bundling strategy targeting peri-operative costs solely related to surgical practice may not yield substantive savings while rationing potentially beneficial treatments to patient care. LEVEL OF EVIDENCE: 5.

Is the lateral jack-knife position responsible for cases of transient neurapraxia?

OBJECTIVE: The lateral jack-knife position is often used during transpsoas surgery to improve access to the spine. Postoperative neurological signs and symptoms are very common after such procedures, and the mechanism is not adequately understood. The objective of this study is to assess if the lateral jack-knife position alone can cause neurapraxia. This study compares neurological status at baseline and after positioning in the 25° right lateral jack-knife (RLJK) and the right lateral decubitus (RLD) position. METHODS: Fifty healthy volunteers, ages 21 to 35, were randomly assigned to one of 2 groups: Group A (RLD) and Group B (RLJK). Motor and sensory testing was performed prior to positioning. Subjects were placed in the RLD or RLJK position, according to group assignment, for 60 minutes. Motor testing was performed immediately after this 60-minute period and again 60 minutes thereafter. Sensory testing was performed immediately after the 60-minute period and every 15 minutes thereafter, for a total of 5 times. Motor testing was performed by a physical therapist who was blinded to group assignment. A follow-up call was made 7 days after the positioning sessions. RESULTS: Motor deficits were observed in the nondependent lower limb in 100% of the subjects in Group B, and no motor deficits were seen in Group A. Statistically significant differences (p < 0.05) were found between the 2 groups with respect to the performance on the 10-repetition maximum test immediately immediately and 60 minutes after positioning. Subjects in Group B had a 10%-70% (average 34.8%) decrease in knee extension strength and 20%-80% (average 43%) decrease in hip flexion strength in the nondependent limb. Sensory abnormalities were observed in the nondependent lower limb in 98% of the subjects in Group B. Thirty-six percent of the Group B subjects still exhibited sensory deficits after the 60-minute recovery period. No symptoms were reported by any subject during the follow-up calls 7 days after positioning. CONCLUSIONS: Twenty-five degrees of right lateral jack-knife positioning for 60 minutes results in neurapraxia of the nondependent lower extremity. Our results support the hypothesis that jack-knife positioning alone can cause postoperative neurological symptoms.

Direct Measurement of Tissue Oxygenation as a Method of Diagnosis of Acute Compartment Syndrome.

OBJECTIVE: The aim of this study was to investigate the utility of direct measurement of tissue oxygenation during compartment syndrome (CS) and tourniquet-induced ischemia in a large animal model. We hypothesize that as compartment pressure (CP) rises, circulation within the compartment will decrease resulting in a decreased level of oxygen in the muscle. METHODS: This study used a dog model of both CS- and tourniquet-based ischemia. In 15 animals, CS was induced in 1 hind limb with varying degrees of severity using an infusion model. Tourniquet ischemia was induced in the contralateral hind limb for varying durations. The partial pressure of oxygen (PmO2) was continuously monitored using a polarographic oxygen probe in the muscle of both hind limbs. CP was monitored in the CS limb. PmO2 and CP were analyzed after fasciotomy, performed after approximately 7 hours of warm ischemia, or release of tourniquet. RESULTS: With the application of tourniquet ischemia, PmO2 fell from 38.40 to 1.30 mm Hg (P < 0.001) and subsequently rose after release of the tourniquet to 39.81 mm Hg (P < 0.001). Elevated CP induced by infusion was relieved by fasciotomy (52.04-11.37 mm Hg postfasciotomy, P < 0.001). PmO2 readings in the infusion model were significantly higher in pre-CS than during CS (31.77 mm Hg vs. 3.88 mm Hg, P < 0.001) and rebounded after fasciotomy (50.24 mm Hg, P < 0.001), consistent with hyperemic response. CONCLUSIONS: Increased CP caused an observable decrease in PmO2 that was reversed by fasciotomy. PmO2 can be directly measured in real time with a polarographic tissue pO2 probe. This study is the first step of evaluating an alternative method for diagnosing acute CS.