Return to flight duty (RTFD) after posterior lumbar spine surgery for symptomatic lumbar disc herniation (LDH) and lumbar isthmic spondylolisthesis (LIS) in Chinese military pilots

BACKGROUND

Symptomatic lumbar disc herniation (LDH) and lumbar isthmic spondylolisthesis (LIS) present significant challenges for military pilots, which may result in grounding if not effectively managed. Surgical treatment for LDH and LIS may offer a pathway to return to flight duty (RTFD), but recent data on this crucial topic is lacking. This study seeks to address this gap by investigating the RTFD outcomes among Chinese military pilots who have undergone lumbar spine surgery for symptomatic LDH and LIS.

METHODS

A retrospective review was conducted on active-duty military pilots who underwent isolated decompressive or fusion procedures at an authorized military medical center from March 1, 2007, to March 1, 2023. The analysis utilized descriptive statistics to examine demographic, occupational, surgical, and outcome data, with a particular focus on preoperative flight status, recommended clearance by spine surgeons, and actual RTFD outcomes and time.

RESULTS

Among the identified cases of active-duty military pilots with LDH or LIS treated by lumbar surgery (n = 24), 70.8% (17 of 24) consistently maintained RTFD status without encountering surgical complications or medical issues during the follow-up period. Of the seven pilots who did not RTFD, one retired within a year of surgery, two had anterior cruciate ligament injuries, three had residual radicular symptoms, and one had chronic low back pain. Excluding pilots who retired and did not RTFD for reasons unrelated to their lumbar conditions, the RTFD rate stood at 81.0% (17 of 21). The median time for recommended clearance by spine surgeons was 143.0 days (inter-quartile range, 116.5-196.0), while the median duration for actual RTFD attainment was 221.0 days (inter-quartile range, 182.0-300.0). The median follow-up post-lumbar surgery was 1.7 years (inter-quartile range, 0.4-2.9).

CONCLUSION

Most military pilots diagnosed with symptomatic LDH and LIS can continue their careers and regain active-duty flight status following lumbar spine surgery, as reflected by the high RTFD rate. Lumbar spine surgery can successfully alleviate the physical constraints associated with spinal conditions, facilitating the return of military pilots to their demanding profession.

Effect of Fusion and Arthroplasty for Cervical Degenerative Disc Disease in Active Duty Service Members Performed at an Overseas Military Treatment Facility: A 2-Year Retrospective Analysis

INTRODUCTION

Among U.S. military active duty service members, cervicalgia, cervical radiculopathy, and myelopathy are common causes of disability, effecting job performance and readiness, often leading to medical separation from the military. Among surgical therapies, anterior cervical discectomy and fusion (ACDF) and cervical disc arthroplasty (CDA) are options in select cases; however, elective surgeries performed while serving overseas (OCONUS) have not been studied.

MATERIALS AND METHODS

A retrospective analysis of a prospectively collected surgical database from an OCONUS military treatment facility over a 2-year period (2019-2021) was queried. Patient and procedural data were collected to include ACDF or CDA surgery, military rank, age, tobacco use, pre- and post-operative visual analogue scales for pain, and presence of radiographic fusion after surgery for ACDF patients or heterotopic ossification for CDA patients. Chi-square and Student t-test analyses were performed to identify variables associated with return to full duty.

RESULTS

A total of 47 patients (25 ACDF and 22 CDA) underwent surgery with an average follow-up of 192.1 days (range 7-819 days). Forty-one (87.2%) patients were able to return to duty without restrictions; 10.6% of patients remained on partial or limited duty at latest follow-up and one patient was medically separated from the surgical cohort. There was one complication and one patient required tour curtailment from overseas duty for ongoing symptoms.

CONCLUSIONS

Both ACDF and CDA are effective and safe surgical procedures for active duty patients with cervicalgia, cervical radiculopathy, and cervical myelopathy. They can be performed OCONUS with minimal interruption to the patient, their family, and the military unit, while helping to maintain surgical readiness for the surgeon and the military treatment facility.

Lumbar Fusion for Active Duty Service Members Performed at an Overseas Military Treatment Facility: A 2-Year Retrospective Analysis

INTRODUCTION

Among U.S. Military active duty service members, low back pain (LBP) and lumbar radiculopathy are common causes of disability and effect job performance and readiness and can lead to medical separation from the military. Among surgical therapies, lumbar fusion is an option in select cases; however, elective lumbar fusion performed while serving overseas has not been studied extensively.

MATERIALS AND METHODS

A retrospective analysis of a prospectively collected surgical database from an overseas military treatment facility (MTF) over a 2-year period (2019-2021) was queried. Patient and procedural data were collected to include single and 2-level lumbar fusion, indications for surgery, military rank, age, tobacco use, pre- and postoperative Visual Analog Scale (VAS) scores for pain, and the presence of radiographic fusion after surgery. Chi-square and Student's t-test analyses were performed to identify variables associated with return to full duty.

RESULTS

A total of 21 patients underwent lumbar fusion with an average follow-up of 303.2 days (110-832 days). Eleven (52.4%) were able to return to full duty without restriction. Four (19%) patients ultimately required medical separation from the military, and six (28.6%) remained in a partial or limited duty status. Three (14.3%) patients required tour curtailment and return from overseas duty prematurely. Older age (40.2 ± 5.9 years), rank of E7 or greater, and reduction in VAS of 50% postoperatively were all associated with return to full unrestricted active duty. Three surgical complications occurred; all patients were able to recover overseas within a 3-month postoperative period.

CONCLUSIONS

Low back pain (LBP) and lumbar radiculopathy may ultimately require treatment with instrumented lumbar fusion and decompression. In this series, we demonstrate that overseas duty with treatment at a community-sized MTF does not preclude this therapy and should be considered among treatment options.

Is Self-reported Return to Duty an Adequate Indicator of Return to Sport and/or Return to Function in Military Patients?

BACKGROUND

In the military, return-to-duty status has commonly been used as a functional outcome measure after orthopaedic surgery. This is sometimes regarded similarly to return to sports or as an indicator of return to full function. However, there is variability in how return-to-duty data are reported in clinical research studies, and it is unclear whether return-to-duty status alone can be used as a surrogate for return to sport or whether it is a useful marker for return to full function.

QUESTIONS/PURPOSES

(1) What proportion of military patients who reported return to duty also returned to athletic participation as defined by self-reported level of physical activity? (2) What proportion of military patients who reported return to duty reported other indicators of decreased function (such as nondeployability, change in work type or level, or medical evaluation board)?

METHODS

Preoperative and postoperative self-reported physical profile status (mandated physical limitation), physical activity status, work status, deployment status, military occupation specialty changes, and medical evaluation board status were retrospectively reviewed for all active-duty soldiers who underwent orthopaedic surgery at Madigan Army Medical Center, Joint Base Lewis-McChord from February 2017 to October 2018. Survey data were collected on patients preoperatively and 6, 12, and 24 months postoperatively in all subspecialty and general orthopaedic clinics. Patients were considered potentially eligible if they were on active-duty status at the time of their surgery and consented to the survey (1319 patients). A total of 89% (1175) were excluded since they did not have survey data at the 1 year mark. Of the remaining 144 patients, 9% (13) were excluded due to the same patient having undergone multiple procedures, and 2% (3) were excluded for incomplete data. This left 10% (128) of the original group available for analysis. Ninety-eight patients reported not having a physical profile at their latest postoperative visit; however, 14 of these patients also stated they were retired from the military, leaving 84 patients in the return-to-duty group. Self-reported "full-time duty with no restrictions" was originally used as the indicator for return to duty; however, the authors felt this to be too vague and instead used soldiers' self-reported profile status as a more specific indicator of return to duty. Mean length of follow-up was 13 ± 3 months. Eighty-three percent (70 of 84) of patients were men. Mean age at the preoperative visit was 35 ± 8 years. The most common surgery types were sports shoulder (n = 22) and sports knee (n = 14). The subgroups were too small to analyze by orthopaedic procedure. Based on active-duty status and requirements of the military profession, all patients were considered physically active before their injury or surgery. Return to sport was determined by asking patients how their level of physical activity compared with their level before their injury (higher, same, or lower). We identified the number of other indicators that may suggest decreased function by investigating change in work type/level, self-reported nondeployability, or medical evaluation board. This was performed with a simple survey.

RESULTS

Of the 84 patients reporting return to duty at the final follow-up, 67% (56) reported an overall lower level of physical activity. Twenty-seven percent (23) reported not returning to the same work level, 32% (27) reported being nondeployable, 23% (19) reported undergoing a medical evaluation board (evaluation for medical separation from the military), and 11% (9) reported a change in military occupation specialty (change of job description).

CONCLUSION

Return to duty is commonly reported in military orthopaedics to describe postoperative functional outcome. Although self-reported return to duty may have value for military study populations, based on the findings of this investigation, surgeons should not consider return to duty a marker of return to sport or return to full function. However, further investigation is required to see to what degree this general conclusion applies to the various orthopaedic subspecialties and to ascertain how self-reported return to duty compares with specific outcome measures used for particular procedures and subspecialties.

LEVEL OF EVIDENCE

Level IV, therapeutic study.

3-D printed Ti-6Al-4V scaffolds for supporting osteoblast and restricting bacterial functions without using drugs: Predictive equations and experiments

Conditions resulting from musculoskeletal deficiencies (MSDs) are wide-ranging and retain the likelihood for restricting motion or producing pain, especially in the lower back, neck, and upper limbs. Engineered scaffold devices are being produced to replace antiquated modalities that suffer from structural and mechanical deficiencies in the treatment of MSDs. Here, as-fabricated Ti-6Al-4V-based Hive™ interbody fusion scaffolds, commercialized by HD Lifesciences LLC, were assayed for their osteogenicity and antibacterial potential using a series of characterization and in vitro tests, as well as by quantitative analyses. A topographical assessment of the Hive™ meshes indicated that the elementally pure substrates are microscopically porous and rough, in addition to displaying structural heterogeneity. Roughness estimations and static contact angle measurements recommended the use of the as-fabricated Ti-6Al-4V substrates for supporting osteoblast attachment, especially, due to the improved surface roughness and wettability values of these scaffolds relative to the unembellished Ti-6Al-4V surfaces. Quantitative correlations relating the surface properties of roughness and energy were applied to predict cellular behaviors. Cell growth suppositions were experimentally corroborated. Critical in vitro data indicated the competencies of the Hive™ scaffolds for promoting the adhesion and proliferation of human fetal osteoblasts (hFOBs), accumulating substantial calcium deposition from metabolizing hFOBs, and restricting the attachment of bacteria. The model system that investigated the pre-adsorption of casein proteins along the Hive™ test substrates additionally furthered the notion that bacterial attachment may be restricted, with short-scale adhesion dynamics serving as the theoretical basis for this hypothesis. In this manner, this study showed that through predictive models and experiments, these novel 3D printed Ti-based scaffolds can increase bone cell while decreasing bacteria functions without using drugs. STATEMENT OF SIGNIFICANCE: Sintered Ti-6Al-4V spinal fusion devices (Hive™) manufactured and marketed by HD Lifesciences LLC were assessed for their biocompatibility and antibacterial performance. A mixed methods approach was employed, whereby quantitative measures were used to predict the ability for Hive™ substrates to adsorb specialized proteins and to restrict bacterial surface colonization. In vitro tests that evaluated bone cell and bacterial adhesion, calcium deposition, and protein adsorption supported quantitative predictions. The data herein presented demonstrate the following: (1) surface energy is an important predictor of implant-cell interactions, (2) strong correlations exist between surface energy and surface roughness, (3) mathematical models can be used to improve and predict implant device perofrmance, and (4) porous, rough, 3D-printed materials perform well in terms of biocompatibility and antimicrobial efficacy.

Comparing Lumbar Disc Space Preparation With Fluoroscopy Versus Cone Beam-Computed Tomography and Navigation: A Cadaveric Study

STUDY DESIGN

Cadaveric study.

OBJECTIVE

This cadaveric study sought to evaluate the efficacy of disc space preparation with cone beam-computed tomography with navigation (CBCT+N) for instrument placement compared with instrument placement with conventional fluoroscopy.

SUMMARY OF BACKGROUND DATA

Disc space preparation from a transforaminal lumbar approach is challenging with respect to visualization, and surgeons currently rely on tactile feel and two-dimensional imaging in the operating room to assess instrument positioning.

METHODS

Two orthopedic spine surgeons performed 40 disc space preparations after eight cadavers were randomly assigned to fluoroscopy versus CBCT+N. Digital images of each vertebral endplate were captured and the percent disc removed by area for the total disc and by quadrants was determined using digital imaging software.

RESULTS

There were 20 lumbar disc levels prepared in the fluoroscopy group. There were 3 thoracolumbar, and 17 lumbar disc levels prepared in the experimental group. Percent disc removed relative to the total area of the disc, as determined by the digital imaging software, was higher in the CBCT+N group (P ≤ 0.0001). More disc was removed in both the anterior contralateral and posterior contralateral quadrants in the CBCT+N group (P = 0.0006 and P ≤ 0.0001 respectively). The intraclass correlation coefficient among blinded reviewers for percent disc removed was 0.759 (95% confidence interval, 0.587-0.866)]. There was no difference in time to complete disc space preparation, number of instrument passes, or number of endplate violations between the two groups (P = 0.28, P = 0.92, and P = 0.34 respectively).

CONCLUSION

The results of this cadaveric investigation reveal that CBCT+N guidance may be used to assess instrument placement for interbody disc space preparation in a similar length of time, with no difference in instrument passes or endplate violations, in comparison with fluoroscopy.

LEVEL OF EVIDENCE

5.

Hip Arthroscopy for Femoroacetabular Impingement in a Military Population

BACKGROUND

Femoroacetabular impingement (FAI) can lead to hip pain and early joint degeneration. There have been few reports to date on the outcomes of hip arthroscopy for the treatment of FAI in the military population. Purpose/Hypothesis: The purpose of this study was to compare patient demographics with postoperative outcomes after hip arthroscopy for symptomatic FAI and to identify preoperative risk factors for poor outcomes. The hypothesis was that certain preoperative patient characteristics will be predictive of poorer outcomes and that lower outcomes scores will be associated with a higher likelihood of medical separation from the military.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

Retrospective chart review of active-duty and dependent patients older than 18 years who underwent hip arthroscopy for symptomatic FAI from 2009 to 2014 at a single institution.

RESULTS

A total of 469 (309 males and 160 females) surgeries were performed on 456 active-duty personnel and 13 dependent civilians, with a mean 2.5-year follow-up. Overall, 39% (n = 179) were able to return to duty (RTD), 18% (n = 82) were medically cleared to return to normal daily activities but did not remain on active duty, and 43% (n = 195) required referral to the Disability Evaluation System (DES). Increasing rank and male sex were positive predictors and Axis 1 psychiatric diagnosis, revision surgery, concomitant psoas tenotomy, multiple medical comorbidities, and complaints of generalized pelvic pain were negative predictors for returning to duty. US Marine Infantry and Special Forces showed improved RTD rates (50%-86%) compared with administrative, more sedentary, occupations (22%). On average, Single Alpha Numeric Evaluation (SANE) and visual analog scale (VAS) scores improved after surgery, with SANE scores improving 37 ± 28 points and VAS scores improving 2.6 ± 2.5 points. The mean postoperative SANE and VAS scores differed significantly between the RTD group and those not returning to duty; 87 and 1.2 points compared with 69 and 3.6 points, respectively ( P < .0001).

CONCLUSION

Hip arthroscopy for the treatment of symptomatic FAI effectively improves pain symptoms and self-reported overall function but shows a much lower than expected return to full, unrestricted active duty in the general active-duty military population. Underlying psychiatric diagnoses, female sex, and more sedentary occupations are associated with lower RTD rates. Furthermore, lower postoperative SANE and VAS scores are associated with lower RTD rates. Only the more active and elite components of the military study population showed RTD rates consistent with previously reported outcomes of return to competitive sports after hip arthroscopy for FAI.

Military rank and the symptoms of lumbar disc herniation in young Korean soldiers

OBJECTIVE

There are many factors associated with the symptom presentation of lumbar disc herniation (LDH). However, there are only few reports regarding the clinical feature of LDH in military medicine. The objective of this study is to determine the factors that affected the symptoms of LDH in young Korean soldiers.

METHODS

One hundred thirty male soldiers, diagnosed with LDH, were enrolled in this study. They were divided into four groups, according to their military ranks: private, private first class, corporal, and sergeant. The visual analog scale for low back pain (VAS-LBP), the VAS for leg pain (VAS-LP), and the Oswestry Disability Index (ODI) were evaluated. The education level and military rank were also reviewed and their relationship with the degree of symptoms was investigated.

RESULTS

The mean age for the male subjects enrolled was 20.7 ± 1.2. The mean VAS-LBP, VAS-LP, and ODI were 6.6% ± 1.7%, 7.1% ± 1.9%, and 46.0% ± 16.3%, respectively. There was no statistically significant relationship between the degree of symptoms and the radiologic findings. However, the military rank had an inverse correlation with the VAS scores and the ODI (P < 0.05).

CONCLUSION

Our data showed that the military rank was associated with the symptom presentation of LDH and reflected the characteristics of military life.