Are Variable Screw Angle Change and Screw-to-Vertebral Body Ratio Associated With Radiographic Subsidence Following Anterior Cervical Discectomy and Fusion?

STUDY DESIGN: Retrospective Cohort. OBJECTIVE: This study aims to assess the easily measurable radiographic landmarks of screw-to-vertebral body ratio and changes in screw angle to identify if they are associated with early subsidence following an Anterior cervical discectomy and fusion (ACDF). METHODS: A retrospective cohort study was conducted on patients undergoing 1-3 level ACDF with allograft or PEEK cages. Preoperative, immediate postoperative, and 6-month postoperative radiographs were analyzed to measure intradiscal height (or distance between 2 vertebral bodies) as an anterior vertebral distance (AVD), middle (MVD), and posterior (PVD), screw angle, screw-to-vertebral body length ratio, and interscrew distance. Multivariate stepwise regression analyses were performed. RESULTS: 92 patients were included (42 single-level, 32 two-level, and 18 3-level ACDFs). In single-level ACDFs, a decrease in the caudal screw angle was associated with a decrease in AVD (=.001) and MVD (P = .03). A decrease in the PVD was associated with a decrease in segmental lordosis (P < .001). For two-level ACDFs, a higher caudal screw-to-body ratio was associated with a lower MVD (P = .01). CONCLUSION: Six months following an ACDF for degenerative pathology, a decrease in the caudal screw angle was associated with an increase in radiographic subsidence at the antero-medial aspect of the disc space albeit largely subclinical. This suggests that the caudal screw angle change may serve as a reliable radiographic marker for early radiographic subsidence. Furthermore, a greater screw-to-vertebral body ratio may be protective against radiographic subsidence in two-level ACDF procedures.

Ergonomics in Spine Surgery: A Systematic Review.

STUDY DESIGN: Systematic Review. OBJECTIVE: This systematic review aims to synthesize existing studies and highlight the significance of ergonomic considerations for spine surgeons' well-being and the impact on patient outcomes. SUMMARY OF BACKGROUND DATA: Spine surgery is a physically demanding field that poses several risks to surgeons, particularly with musculoskeletal disorders. Despite the well-documented consequences of musculoskeletal injuries endured by surgeons, surgical ergonomics in spine surgery has received limited attention. METHODS: Following PRISMA guidelines, a comprehensive literature search was conducted in PubMed and Embase. Studies focusing on surgeon ergonomics in spine surgery were selected. Data extracted included study details, surgeon demographics, ergonomic factors, and outcomes. Qualitative analysis was performed due to the heterogeneous nature of study designs and criteria. RESULTS: Eleven studies met inclusion criteria. Six studies utilized surveys to explore physical challenges, prevalence rates of pain, work practices, and ergonomic tools. Two studies employed optoelectronic motion analysis to assess spinal angles of the surgeon during surgery. Two studies assesed ergonomics in different visualization methods using rapid entire body assessment (REBA). One study applied video analysis to scrutinize surgeons' neck postures during the case. The results demonstrated a varying prevalence and diverse presentations of musculoskeletal disorders, varying impact on surgical performance, and nuanced relationships between experience, workload, and ergonomic concerns. CONCLUSION: This systematic review summarizes the heterogenous evaluations of ergonomics in spine surgery. Overall, upwards of three-quarters of spine surgeons have reported musculoskeletal discomfort, most commonly presented as back pain, neck pain, and hand/wrist discomfort. These symptoms are often exacerbated by the use of loupes, operating bed height, and extended period of times in various positions. Studies demonstrate that the physical discomfort is associated with the surgeons' mental and emotional well-being, leading to stress, burnout, and reduced job satisfaction; all of which impact patient care.

Opiate-reduction protocol for common outpatient spinal procedures: a long-term feasibility study and single-center experience.

OBJECTIVE: The opioid epidemic continues to be at the forefront of public health. As a response to this crisis, many statewide and national medical groups have sought to develop opioid-prescribing guidelines for both acute and chronic pain states. Given the lack of evidence in the neurosurgical landscape, the authors' institution implemented opioid-prescribing guidelines for common outpatient spinal procedures in 2017, subsequently demonstrating a significant reduction in the narcotics prescribed. However, the ability to maintain the results garnered from such guidelines long term has not been described. The objective of this study was to evaluate postoperative opioid utilization at a high-volume quaternary referral center 5 years after the initial implementation of an opioid-reduction protocol for common outpatient spinal procedures. METHODS: From the electronic medical records, authors collected data on the number of tablets and total morphine equivalent dose (MED) prescribed, acute postoperative readmissions for pain concerns, refill requests, and conversion to long-term opiate use in the 5 years following implementation of an opioid-reduction protocol for common outpatient spinal procedures. These procedures, undertaken in opiate-naive patients, included 1- or 2-level anterior cervical discectomy and fusion, 1- or 2-level cervical disc replacement, and 1- or 2-level laminectomy, laminotomy, or foraminotomy (cervical or lumbar). RESULTS: The total quantity of narcotics was reduced by 37.0 tablets per patient after protocol implementation and over the 5-year period thereafter. Generally, patients were discharged with an average of 23.3 tablets, concurrent with the initial goal of 24 tablets, set forth in 2017. These results confirm an ongoing reduction in opiate quantities prescribed and overall morphine equivalent totals at the time of discharge over the course of 5 years after initial protocol implementation. CONCLUSIONS: A standardized discharge protocol for postoperative outpatient spinal procedures can lead to long-term reductions in opioid discharge quantity, without compromising patient safety or increasing the utilization of hospital resources through readmissions, refill requests, or clinic phone calls. This study provides an example of a feasible and effective discharge prescription regimen that may be generalizable to common outpatient neurosurgical procedures with long-term evidence that a small intervention can lead to ongoing reduced quantities of postoperative opioids at the time of discharge.

A Tubular-Mounted Digital Camera Versus Optical Surgical Microscope for Minimally Invasive Lumbar Decompression Surgery: The Impact on Operative Times, Ergonomics, and Workflow.

OBJECTIVE: Understanding ergonomic impact is foundational to critically evaluating value and safety of enabling technologies in minimally invasive spine surgeries. This study assessed the impact of a tubular-mounted digital camera (TMDC) versus an optical surgical microscope (OSM) in single-level minimally invasive spine surgeries on operative times, durotomy rate, surgeon ergonomics, safety, and operating room workflow. METHODS: This retrospective study compared consecutive single-level minimally invasive lumbar decompression surgeries in a TMDC cohort (September 2021-June 2022) with an historical OSM cohort (January 2020-July 2021). Data included patient demographics, operative times, durotomy incidence, surgeon ergonomics (Rapid Entire Body Assessment scores), and equipment impact via staff surveys. Operative times were assessed by t test, while Pearson χ2 test compared sex. Age, body mass index, and Charlson Comorbidity Index comparisons were made by Wilcoxon rank sum tests, and survey results were analyzed with Wilcoxon signed rank tests. RESULTS: TMDC and OSM groups included 74 and 82 patients, respectively. Age, sex, and Charlson Comorbidity Index did not significantly differ between groups. The TMDC group had a higher body mass index (29.6 ± 5.1) than the OSM group (29.0 ± 7.5) (P = 0.04). The TMDC group had significantly shorter operative times (57.3 ± 16.6 minutes) than the OSM group) (66.7 ± 22.5 minutes) (P = 0.004), with no difference in durotomy rates (P = 0.42). TMDC use yielded lower Rapid Entire Body Assessment scores compared with OSM (4.1 ± 0.77) (P < 0.001). Surveys indicated improved safety, setup time, and workflow with TMDC (P < 0.001). CONCLUSIONS: TMDC in single-level minimally invasive lumbar decompression surgery improved surgeon ergonomics, reduced operative times, and maintained durotomy rates, enhancing operating room efficiency. Evaluating ergonomic impact of technology is vital for safety and value assessment.

Time of hemodialysis and risk of intradialytic hypotension and intradialytic hypertension in maintenance hemodialysis.

Intradialytic hypotension and intradialytic hypertension are complications of hemodialysis (HD) associated with a higher risk of cardiovascular disease (CVD) and death. Blood pressure (BP) normally fluctuates in a circadian pattern, but whether the risk of intradialytic hypotension and intradialytic hypertension varies according to the time of the HD session is unknown. We analyzed two cohorts of thrice-weekly maintenance HD (N = 1838 patients/n = 64,503 sessions from the Hemodialysis [HEMO] Study, and N = 3302 patients/n = 33,590 sessions from Satellite Healthcare). Random effects logistic regression models examined the association of HD start time (at or before 9:00 a.m. [early AM], between 9:01 a.m. and 12:00 p.m. [late AM], and at or after 12:01 p.m. [PM]) with intradialytic hypotension (defined as nadir intra-HD systolic BP (SBP) < 90 mmHg if pre-HD SBP < 160 mmHg, or <100 mmHg if pre-HD SBP ≥ 160 mmHg) and intradialytic hypertension (SBP increase ≥ 10 mmHg from pre-HD to post-HD). Compared to early AM, late AM and PM were associated with an 8% (aOR 0.92, 95% CI 0.83-1.02) and a 16% (aOR 0.84, 95% CI 0.75-0.95) lower risk of intradialytic hypotension in HEMO, respectively. Conversely, compared to early AM, a monotonic higher risk of intradialytic hypertension was observed for late AM (aOR 1.23, 95% CI 1.12-1.35) and PM (aOR 1.41, 95% CI 1.27-1.56) in HEMO. These findings were consistent in Satellite. In two large cohorts of maintenance HD, we observed a monotonic lower risk of intradialytic hypotension and a monotonic higher risk of intradialytic hypertension with later dialysis start times. Whether HD treatment allocation to certain times of the day in hypotensive-prone or hypertensive-prone patients improves outcomes deserves further investigation.