Effect of placental tissue on inhibition of uterine contraction by nitric oxide donors

OBJECTIVE

Our purpose was to test the hypothesis that placental tissue modulates the effect of nitric oxide on spontaneous uterine contractility in pregnant rats.

STUDY DESIGN

Rings (approximately 4 mm) of uterus taken from rats on day 14 (midpregnancy, n = 6), day 18 (late pregnancy, n = 4), and day 22 (term, n = 4) of gestation were placed in organ chambers filled with Krebs-bicarbonate buffer bubbled with 5% carbon dioxide in air (37 degrees C, pH approximately 7.4) for isometric tension recording. In some rings a piece of placenta was left attached to the uterine wall. In the other rings the fetuses, placentas, and membranes were removed completely. Change of spontaneous contractions of the rings (percentage change of basal integral activity for 10 minutes) in response to cumulative concentrations of the nitric oxide donors diethylamine-nitric oxide and nitroglycerin (10(-6) mol/L to 10(-4) mol/L) were compared between rings with and without placenta.

RESULTS

Diethylamine-nitric oxide and nitroglycerin inhibited spontaneous uterine contractions in rings from midpregnancy, in both the absence and the presence of placenta. In rings from midpregnancy, the maximal inhibition of contractions by diethylamine-nitric oxide but not by nitroglycerin was significantly (P <.05) higher in the presence (26.7% +/- 3.5% of basal activity) than in the absence (39. 6% +/- 3.3%) of placenta. Inhibition of contraction by nitric oxide donors in rings from late and term pregnancy was less than in midpregnancy, and the presence of placental tissue did not influence the responses.

CONCLUSIONS

The presence of placental tissue enhances inhibition of uterine contractility by agents that spontaneously release nitric oxide, such as diethylamine-nitric oxide, but not by nitroglycerin, which requires metabolic transformation for nitric oxide to be released. Refractoriness to nitric oxide near or at term does not depend on the presence or absence of placental tissue.

Evaluating the Impact of Modic Changes on Operative Treatment in the Cervical and Lumbar Spine: A Systematic Review and Meta-Analysis

Modic changes (MCs) are believed to be potential pain generators in the lumbar and cervical spine, but it is currently unclear if their presence affects postsurgical outcomes. We performed a systematic review in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. All studies evaluating cervical or lumbar spine postsurgical outcomes in patients with documented preoperative MCs were included. A total of 29 studies and 6013 patients with 2688 of those patients having preoperative MCs were included. Eight included studies evaluated cervical spine surgery, eleven evaluated lumbar discectomies, nine studied lumbar fusion surgery, and three assessed lumbar disc replacements. The presence of cervical MCs did not impact the clinical outcomes in the cervical spine procedures. Moreover, most studies found that MCs did not significantly impact the clinical outcomes following lumbar fusion, lumbar discectomy, or lumbar disc replacement. A meta-analysis of the relevant data found no significant association between MCs and VAS back pain or ODI following lumbar discectomy. Similarly, there was no association between MCs and JOA or neck pain following ACDF procedures. Patients with MC experienced statistically significant improvements following lumbar or cervical spine surgery. The postoperative improvements were similar to patients without MCs in the cervical and lumbar spine.

Patient-Reported Outcomes Following Anterior and Posterior Surgical Approaches for Multilevel Cervical Myelopathy

STUDY DESIGN

Retrospective cohort.

OBJECTIVE

To compare health-related quality of life (HRQoL) outcomes between approach techniques for the treatment of multilevel degenerative cervical myelopathy (DCM).

SUMMARY OF BACKGROUND DATA

Both anterior and posterior approaches for the surgical treatment of cervical myelopathy are successful techniques in the treatment of myelopathy. However, the optimal treatment has yet to be determined, especially for multilevel disease, as the different approaches have separate complication profiles and potentially different impacts on HRQoL metrics.

MATERIALS AND METHODS

Retrospective review of a prospectively managed single institution database of patient-reported outcome measures after 3 and 4-level anterior cervical discectomy and fusion (ACDF) and posterior cervical decompression and fusion (PCDF) for DCM. The electronic medical record was reviewed for patient baseline characteristics and surgical outcomes whereas preoperative radiographs were analyzed for baseline cervical lordosis and sagittal balance. Bivariate and multivariate statistical analyses were performed to compare the two groups.

RESULTS

We identified 153 patients treated by ACDF and 43 patients treated by PCDF. Patients in the ACDF cohort were younger (60.1 ± 9.8 vs . 65.8 ± 6.9 yr; P < 0.001), had a lower overall comorbidity burden (Charlson Comorbidity Index: 2.25 ± 1.61 vs . 3.07 ± 1.64; P = 0.002), and were more likely to have a 3-level fusion (79.7% vs . 30.2%; P < 0.001), myeloradiculopathy (42.5% vs . 23.3%; P = 0.034), and cervical kyphosis (25.7% vs . 7.69%; P = 0.027). Patients undergoing an ACDF had significantly more improvement in their neck disability index after surgery (-14.28 vs . -3.02; P = 0.001), and this relationship was maintained on multivariate analysis with PCDF being independently associated with a worse neck disability index (+8.83; P = 0.025). Patients undergoing an ACDF also experienced more improvement in visual analog score neck pain after surgery (-2.94 vs . -1.47; P = 0.025) by bivariate analysis.

CONCLUSIONS

Our data suggest that patients undergoing an ACDF or PCDF for multilevel DCM have similar outcomes after surgery.

A Comparison of Outcomes Between Transfemoral Versus Transradial Access for Carotid Stenting

BACKGROUND

The transradial (TR) approach has emerged as an alternative to the transfemoral (TF) approach in carotid artery stenting (CAS) because of its perceived benefits in access site complications and overall patient experience.

OBJECTIVE

To assess outcomes of TF vs TR approach for CAS.

METHODS

This is a retrospective single-center review of patients receiving CAS through the TR or TF route between 2017 and 2022. All patients with symptomatic and asymptomatic carotid disease who underwent attempted CAS were included in our study.

RESULTS

A total of 342 patients were included in this study: 232 underwent CAS through TF approach vs 110 through the TR route. On univariate analysis, the rate of overall complications was more than double for the TF vs TR cohort; however, this did not achieve statistical significance (6.5% vs 2.7%, odds ratio [OR] = 0.59 P = .36). The rate of cross-over from TR to TF was significantly higher on univariate analysis (14.6 % vs 2.6%, OR = 4.77, P = .005) and on inverse probability treatment weighting analysis (OR = 6.11, P < .001). The rate of in-stent stenosis (TR: 3.6% vs TF: 2.2%, OR = 1.71, P = .43) and strokes at follow-up (TF: 2.2% vs TR: 1.8%, OR = 0.84, P = .84) was not significantly different. Finally, median length of stay was comparable between both cohorts.

CONCLUSION

The TR approach is safe, feasible, and provides similar rates of complications and high rates of successful stent deployment compared with the TF route. Neurointerventionalists adopting the radial first approach should carefully assess the preprocedural computed tomography angiography to identify patients amenable to TR approach for carotid stenting.

Utilization of In-Hospital Orthopaedic Spine Consultations: Evaluating the Impact of Health Care Policy

Access to specialty and private practice providers has been a divisive policy issue over the last decade, complicated by the conflict between a reduction in government-funded health care reimbursement and the need for health care providers to sustain a financially sound practice. This study evaluates the orthopedic spine consult service at an academic tertiary care center at 2 separate time points over a 5-year period to better understand the impact of decreasing orthopedic reimbursement rates and the increasing prevalence of federally supported medical insurance on the access to specialty care. In total 500 patients in 2017 and 480 patients in 2021 were included for the final analysis. A higher percentage of consults in 2021 came from the emergency department (74.0% versus 60.4%, P < 0.001); however, the emergency department saw fewer spinal cord injuries (11.9% versus 21.4%, P < 0.001), and the spinal cord injuries were less severe (3.1% versus 6.2% Association Impairment Scale A or B, P = 0.034). A smaller percentage of patients in 2021 went on to receive orthopedic spine surgery following consultation (35.2% versus 43.8%, P = 0.007), and those receiving surgery had an operation performed farther out from the initial consultation (4.73 versus 4.09 days, P < 0.001). Additionally, fewer patients with Medicare insurance (23.5% versus 30.8%) and more patients with Medicaid insurance (20.2% versus 12.4%) were seen in 2021 compared with 2017 (P = 0.003). Overall, this study found an increased proportion of Medicaid patients seen by the spine consult service but a decrease in the acuity of consults. Measures to improve access to health insurance under the Affordable Care Act have revealed the complexity of this issue in health care. This study's findings have demonstrated that while more patients did have insurance coverage following the Affordable Care Act, they still face a barrier to accessing outpatient orthopedic spine providers.

A Swollen Supraglottis

A woman in her late 20s presented with difficulty phonating and singing for the past 15 months and no improvement from prior treatment with steroids and antibiotics for chronic laryngitis. What is your diagnosis?

Prognostic and Treatment Differences Between T1a and T1b Glottic Cancer

OBJECTIVES

This study was designed to evaluate significant differences in treatment and survival outcomes between patients with T1a and T1b glottic cancer.

METHODS

Patients within the SEER Research Plus, 18 Registries dataset who were diagnosed with Stage I T1a or T1b cancer of the glottis between 2004 and 2015 were included in this study. Data prior to 2004 could not be included, as the SEER database did not distinguish between T1a and T1b glottic cancer until that year.

RESULTS

The 5-year disease-specific survival for T1a patients was significantly better than that of patients diagnosed with T1b glottic cancer. Age and year of diagnosis were also independent factors that impacted mortality. More patients who were diagnosed with T1b glottic cancer underwent external beam radiation than those diagnosed with T1a glottic cancer.

CONCLUSION

Our data shows that there are several independent factors effecting mortality including T classification, age at time of diagnosis, and year of diagnosis. T1a glottic cancers also show a significantly better prognosis compared with T1b. T1b glottic cancers are much more likely to be treated with primary radiotherapy compared with surgery.

LEVEL OF EVIDENCE

4 Laryngoscope, 2022.

Does Age and Medicare Status Affect Clinical Outcomes in Patients Undergoing Anterior Cervical Discectomy and Fusion?

OBJECTIVE

The objective of this study was to determine if Medicare status and age affect clinical outcomes following anterior cervical discectomy and fusion.

METHODS

Patients who underwent cervical discectomy and fusion between 2014 and 2020 with complete preoperative and 1-year postoperative patient-reported outcome measures (PROMs) were grouped based on Medicare status and age: no Medicare under 65 years (NM < 65), Medicare under 65 years (M < 65), no Medicare 65 years or older (NM ≥ 65), and Medicare 65 years or older (M ≥ 65). Multivariate regression for ΔPROMs (Δ: postoperative minus preoperative) controlled for confounding differences between groups. Significant was set at P < 0.05.

RESULTS

A total of 1288 patients were included, with each group improving in the visual analog score (VAS) Neck (all, P < 0.001), VAS Arm (M < 65: P = 0.003; remaining groups: P < 0.001), and Neck Disability Index (M < 65: P = 0.009; remaining groups: P < 0.001) following surgery. Only M < 65 did not significantly improve in the Physical Component Score (PCS-12) and modified Japanese Orthopaedic Association (mJOA) score (P = 0.256 and P = 0.092, respectively). When comparing patients under 65 years, non-Medicare patients had better preoperative PCS-12 (P < 0.001), Neck Disability Index (P < 0.001), and modified Japanese Orthopaedic Association (P < 0.001), as well as better postoperative values for all PROMs (P < 0.001), but there were no differences in ΔPROMs. Multivariate analysis identified M < 65 to be an independent predictor of decreased improvement in ΔPCS-12 (β = -4.07, P = 0.015), ΔVAS Neck (β = 1.17, P = 0.010), and ΔVAS Arm (β = 1.15, P = 0.025) compared to NM < 65.

CONCLUSIONS

Regardless of age and Medicare status, all patients undergoing cervical discectomy and fusion had significant clinical improvement postoperatively. However, Medicare patients under age 65 have a smaller magnitude of improvement in PROMs.

The Enterprise stent…still useful after all these years

BACKGROUND

The Enterprise stent (Codman Neuro, Massachusetts, USA) received Food and Drug Administration (FDA) approval in 2007 for stent-assisted coiling (SAC). Since its introduction, newer stents and devices for aneurysm treatment have been developed resulting in a shift in the utilization of this stent from SAC to other off-label indications.

OBJECTIVE

To describe our experience with the Enterprise stent being used for SAC and other off-label indications.

METHODS

This is a multi-center retrospective review of the use of the Enterprise stent between 2018 and 2023. All patients in which the Enterprise stent was successfully deployed were included in the study.

RESULTS

Our study cohort comprised of 194 patients, mostly females (n = 112, 57.7%), with a mean age of 63.2 years ± 14.3. The Enterprise stent was used for SAC in only 24 (12.4%) patients and was used for rescue stenting in stroke in 101 patients (52.1%), treatment of intracranial stenosis in 53 patients (27.3%), treatment of in-stent stenosis in 1 patient (0.5%), and for treatment of dissections in 15 patients (7.7%). From 2018 to 2023, the use of Enterprise stents for SAC significantly decreased (p < 0.0001) while the use of Enterprise stents for non-SAC purposes was insignificantly variable (p = 0.05).

CONCLUSION

Our study shows that the Enterprise stent remains a reliable tool in neuroendovascular procedures, even if its original intended use has been supplanted by other devices.

Biomechanical Effects of Surgical Reconstruction for Flexible Progressive Collapsing Foot Deformity: A Systematic Review

BACKGROUND

Symptomatic progressive collapsing foot deformity (PCFD) is frequently treated with reconstructive surgery. Multiple studies have documented successful treatment based on improvements in symptoms and physical examination findings. However, it is not well-established whether there are corresponding improvements in gait function following surgical treatment for PCFD.

METHODS

A systematic review of biomechanical outcomes of treatments for flexible PCFD was conducted on PubMed. The 4 articles chosen involved patients with symptomatic flexible PCFD who underwent a reconstructive surgery. Surgical interventions included osteotomy, tendon transfer, and/or ligament repair or reconstruction. Primary outcomes involved objective quantifiable measurements of kinematic, kinetic, or temporospatial parameters.

RESULTS

The initial search yielded 605 articles, from which 26 were retained after screening the title and abstract. Twenty-two were eliminated yielding 4 articles. Temporospatial, kinematic, and kinetic parameters were all altered after the patients underwent surgical intervention. Specifically, stride length, cadence, and walking speed all improved postoperatively. Walking kinetics also improved with restoration of normal motion in the frontal and sagittal planes and improvements in the dorsiflexion angle. There were also improvements in sagittal power.

DISCUSSION

Surgical intervention to treat flexible PCFD improves objective biomechanical outcomes; however, more follow-up studies are needed to establish the reliability and durability of these improvements.

LEVEL OF EVIDENCE

Level III: Systematic review.

Robot Assisted Renal Allograft Nephrectomy: Initial Case Series and Description of Technique

OBJECTIVE

To evaluate the outcomes and perioperative complication rates following robot- assisted transplant nephrectomy ((RATN).

METHODS

All patients who underwent RATN at our institution were included. No exclusion criteria were applied. Clinical records were retrospectively reviewed and reported. This included preoperative, intraoperative, and postoperative outcomes. Complications were reported utilizing the Clavien-Dindo classification system. Descriptive statistics were reported using frequencies and percentages for categorical variables, means and standard deviation for continuous variables.

RESULTS

Between July 2014 and April 2018, 15 patients underwent RATN. Most patients had the transplant in the right iliac fossa (13/15). Ten patients underwent a concomitant procedure. The total operative time for the entire cohort was 336 (±102) minutes (including cases who had concomitant procedures) and 259 (±46 minutes) when cases with concomitant procedures were excluded. Mean estimated blood loss was 383 (±444) mL. Postoperatively, 3 patients required blood transfusion. Average hospital stay was 4 (±2.7) days. Most patients had finding consistent with graft rejection on final pathology. There were 5 complications; 3 of which were minor (grade 2 = 2 and grade 3 = 1); one patient had a wound infection requiring dressing (3A) and one patient died due to pulmonary embolism following discharge. Limitations include small series and retrospective nature of the study.

CONCLUSION

This case series demonstrate that RATN is technically feasible. With continued experience and larger case series, the robotic approach may provide a minimally invasive alternative to open allograft nephrectomy.

Ultrasound Shear Wave Elastography of the Arch-Supporting Structures in Symptomatic Flatfoot: A Pilot Study

Background

The posterior tibial tendon (PTT), deltoid ligament, and spring ligament are often torn or attenuated in patients with progressive collapsing foot deformity. The goal of this pilot study was to measure the ultrasound shear wave velocity (SWV) of these arch-supporting structures in feet with varying degrees of deformity to improve our understanding of their role in the progression of deformity.

Methods

Two observers measured the SWV of the supramalleolar and inframalleolar PTT in long and short axes, in the tibiospring portion of the deltoid ligament, and in the superomedial band of the spring ligament in 8 neutrally aligned feet, 5 asymptomatic flatfeet, and 7 symptomatic flatfeet. Each measurement was repeated 3 times both with and without an applied eversion stress.

Results

Average SWV was lower at all locations in the symptomatic flatfeet compared with normal feet, but these differences were statistically significant only for the inframalleolar PTT and the spring ligament. Externally applied stress led to an increase in the SWV of the ligaments but a paradoxical decrease in the SWV in the supramalleolar PTT. The SWV of the PTT was lower along the short axis compared with the long axis.

Conclusion

SWV may be useful in evaluating the severity of degenerative disease of arch-supporting structures, but further study is needed before this technique can be applied clinically.

Level of Evidence

Level III, case-control study.

Reasons for transfer and subsequent outcomes among patients undergoing elective spine surgery at an orthopedic specialty hospital

Objective

To evaluate the reasons for transfer as well as the 90-day outcomes of patients who were transferred from a high-volume orthopedic specialty hospital (OSH) following elective spine surgery.

Materials and Methods

All patients admitted to a single OSH for elective spine surgery from 2014 to 2021 were retrospectively identified. Ninety-day complications, readmissions, revisions, and mortality events were collected and a 3:1 propensity match was conducted.

Results

Thirty-five (1.5%) of 2351 spine patients were transferred, most commonly for arrhythmia (n = 7; 20%). Thirty-three transferred patients were matched to 99 who were not transferred, and groups had similar rates of complications (18.2% vs. 10.1%; P = 0.228), readmissions (3.0% vs. 4.0%; P = 1.000), and mortality (6.1% vs. 0%; P = 0.061).

Conclusion

Overall, this study demonstrates a low transfer rate following spine surgery. Risk factors should continue to be optimized in order to decrease patient risks in the postoperative period at an OSH.

The prescription drug monitoring program in a multifactorial approach to the opioid crisis: PDMP data, Pennsylvania, 2016-2020

BACKGROUND

Prescription opioids remain an important contributor to the United States opioid crisis and to the development of opioid use disorder for opioid-naïve individuals. Recent legislative actions, such as the implementation of state prescription drug monitoring programs (PDMPs), aim to reduce opioid morbidity and mortality through enhanced tracking and reporting of prescription data. The primary objective of our study was to describe the opioid prescribing trends in the state of Pennsylvania (PA) as recorded by the PA PDMP following legislative changes in reporting guidelines, and discuss the PDMP's role in a multifactorial approach to opioid harm reduction.

METHODS

State-level opioid prescription data summaries recorded by the PA PDMP for each calendar quarter from August 2016 through March 2020 were collected from the PA Department of Health. Data for oxycodone, hydrocodone, and morphine were analyzed by quarter for total prescription numbers and refills. Prescription lengths, pill quantities, and average morphine milliequivalents (MMEs) were analyzed by quarter for all 14 opioid prescription variants recorded by the PA PDMP. Linear regression was conducted for each group of variables to identify significant differences in prescribing trends.

RESULTS

For total prescriptions dispensed, the number of oxycodone, hydrocodone, and morphine prescriptions decreased by 34.4, 44.6, and 22.3% respectively (p < 0.0001). Refills fluctuated less consistently with general peaks in Q3 of 2017 and Q3 of 2018 (p = 0.2878). The rate of prescribing for all opioid prescription lengths decreased, ranging in frequency from 22 to 30 days (47.5% of prescriptions) to 31+ days of opioids (0.8% of prescriptions) (p < 0.0001). Similarly, decreased prescribing was observed for all prescription amounts, ranging in frequency from 22 to 60 pills (36.6% of prescriptions) to 60-90 pills (14.2% of prescriptions) (p < 0.0001). Overall, the average MME per opioid prescription decreased by 18.9%.

CONCLUSIONS

Per the PA PDMP database, opioid prescribing has decreased significantly in PA from 2016 to 2020. The PDMP database is an important tool for tracking opioid prescribing trends in PA, and PDMPs structured similarly in other states may enhance our ability to understand and influence the trajectory of the U.S. opioid crisis. Further research is needed to determine optimal PDMP policies and practices nationwide.

Predictors of Transfemoral Access Site Complications in Neuroendovascular Procedures: A large Single-Center Cohort Study

OBJECTIVE

The transfemoral (TF) route has historically been the preferred access site for endovascular procedures. However, despite its widespread use, TF procedures may confer morbidity as a result of access site complications. The aim of this study is to provide the rate and predictors of TF access site complications for neuroendovascular procedures.

METHODS

This is a single center retrospective study of TF neuroendovascular procedures performed between 2017 and 2022. The incidence of complications and associated risk factors were analyzed across a large cohort of patients.

RESULTS

The study comprised of 2043 patients undergoing transfemoral neuroendovascular procedures. The composite rate of access site complications was 8.6 % (n = 176). These complications were divided into groin hematoma formation (n = 118, 5.78 %), retroperitoneal hematoma (n = 14, 0.69 %), pseudoaneurysm formation (n = 40, 1.96 %), and femoral artery occlusion (n = 4, 0.19 %). The cross-over to trans radial access rate was 1.1 % (n = 22). On univariate analysis, increasing age (OR=1.0, p = 0.06) coronary artery disease (OR=1.7, p = 0.05) peripheral vascular disease (OR=1.9, p = 0.07), emergent mechanical thrombectomy procedures (OR=2.1, p < 0.001) and increasing sheath size (OR=1.3, p < 0.001) were associated with higher TF access site complications. On multivariate analysis, larger sheath size was an independent risk factor for TF access site complications (OR=1.8, p = 0.02).

CONCLUSION

Several pertinent factors contribute towards the incidence of TF access site complications. Factors associated with TF access site complications include patient demographics (older age) and clinical risk factors (vascular disease), as well as periprocedural factors (sheath size).

Radiation-Induced Laryngeal Mucous Membrane Pemphigoid

OBJECTIVES

Bullous pemphigoid has previously been linked to radiotherapy, but here we report the first case of MMP suspected to be a consequence of RT.

METHODS

The patient described is an 85-year-old male who underwent RT to treat squamous cell carcinoma of the palatine tonsil. Shortly after therapy, the patient developed blisters with worsening dyspnea and dysphonia.

RESULTS

This patient was successfully treated with a combination of oral immunosuppressants and surgical intervention.

CONCLUSION

This incident underscores that not all episodes of mucosal ulceration following radiation are a result of mucositis and MMP should be considered in the differential.

LEVEL OF EVIDENCE

Level 4.

Sagittal alignment differences on the operating room table compared to preoperative and postoperative imaging in anterior cervical discectomy and fusion

Study Design

The study design used was a retrospective cohort.

Objective

The objective of this study is to determine if intraoperative improvements in sagittal alignment on the operating table persisted on postoperative standing radiographs.

Summary of Background Data

Cervical sagittal alignment may be correlated to postoperative outcomes. Since anterior cervical discectomy and fusions (ACDFs) can restore some cervical lordosis through intervertebral grafts/cages, it is important to understand if intraoperative radiographic measurements correlate with persistent postoperative radiographic changes.

Materials and Methods

Patients undergoing elective primary ACDF were screened for the presence of lateral cervical radiographs preoperatively, intraoperatively, and postoperatively. Patients were excluded if their first postoperative radiograph was more than 3 months following the procedure or if cervical lordosis was not able to be measured at each time point. Paired t-tests were utilized to compare differences in measurements between time points. Statistical significance was set at P < 0.05.

Results

Of 46 included patients, 26 (56.5%) were female, and the mean age was 55.2 ± 11.6 years. C0-C2 lordosis significantly increased from the preoperative to intraoperative time point (delta [Δ] = 4.49, P = 0.029) and significantly decreased from the intraoperative to postoperative time period (Δ = -6.57, P < 0.001), but this resulted in no significant preoperative to postoperative change (Δ = -2.08, P = 0.096). C2 slope decreased from the preoperative to the intraoperative time point (Δ = -3.84, P = 0.043) and significantly increased from the intraoperative to the postoperative time point (Δ = 3.68, P = 0.047), which also resulted in no net change in alignment between the preoperative and postoperative periods (Δ = -0.16, P = 0.848). There was no significant difference in the C2-C7 SVA from the preoperative to intraoperative (Δ = 0.85, P = 0.724) or intraoperative to postoperative periods (Δ = 2.04, P = 0.401); however, the C2-C7 SVA significantly increased from the preoperative to postoperative period (Δ = 2.88, P = 0.006).

Conclusions

Intraoperative positioning predominantly affects the mobile upper cervical spine, particularly C0-C2 lordosis and C2 slope, but these changes do not persist postoperatively.