Restoration of respiration in high cervical spinal cord injury via phrenic nerve reinnervation: illustrative case.

BACKGROUND: Traumatic high cervical spinal cord injury (SCI) can result in a devastating loss of functional respiration, leaving patients permanently dependent on mechanical ventilation. Nerve transfer is a promising reinnervation strategy that has the potential to restore connectivity in paralyzed distal muscles. The spinal accessory nerve (SAN) remains functional in most cases after high cervical SCI and can serve as a donor to reinnervate the phrenic nerve (PN), thereby improving diaphragmatic function. OBSERVATIONS: Information regarding thorough physical, electrodiagnostic, and pulmonary assessments to establish candidacy for nerve transfer, as well as the surgical procedure, was summarized with an illustrative case. The patient demonstrated improvement in pulmonary function testing but did not achieve independent respiration. A systematic literature review identified 3 studies with 9 additional patients who had undergone SAN-to-PN transfer. The nerve transfer meaningfully restored diaphragmatic function, improving pulmonary function tests and reducing ventilator dependency. LESSONS: Respiratory dependency significantly impacts the quality of life of patients with a high cervical SCI. The use of the lower SAN motor branch for PN transfer is safe and does not result in a meaningful downgrade in trapezius function. Outcomes following this procedure are promising but heterogeneous, indicating a need for significant innovation and improvement for future therapies. https://thejns.org/doi/10.3171/CASE24236.

Spinal cord metrics derived from diffusion MRI: improvement in prognostication in cervical spondylotic myelopathy compared with conventional MRI.

OBJECTIVE: A major shortcoming in optimizing care for patients with cervical spondylotic myelopathy (CSM) is the lack of robust quantitative imaging tools offered by conventional MRI. Advanced MRI modalities, such as diffusion MRI (dMRI), including diffusion tensor imaging (DTI) and diffusion basis spectrum imaging (DBSI), may help address this limitation by providing granular evaluations of spinal cord microstructure. METHODS: Forty-seven patients with CSM underwent comprehensive clinical assessments and dMRI, followed by DTI and DBSI modeling. Conventional MRI metrics included 10 total qualitative and quantitative assessments of spinal cord compression in both the sagittal and axial planes. The dMRI metrics included 12 unique measures including anisotropic tensors, reflecting axonal diffusion, and isotropic tensors, describing extraaxonal diffusion. The primary outcome was the modified Japanese Orthopaedic Association (mJOA) score measured at 2 years postoperatively. Extreme gradient boosting-supervised classification algorithms were used to classify patients into disease groups and to prognosticate surgical outcomes at 2-year follow-up. RESULTS: Forty-seven patients with CSM, including 24 (51%) with a mild mJOA score, 12 (26%) with a moderate mJOA score, and 11 (23%) with a severe mJOA score, as well as 21 control subjects were included. In the classification task, the traditional MRI metrics correctly assigned patients to healthy control versus mild CSM versus moderate/severe CSM cohorts, with an accuracy of 0.647 (95% CI 0.64-0.65). In comparison, the DTI model performed with an accuracy of 0.52 (95% CI 0.51-0.52) and the DBSI model's accuracy was 0.81 (95% CI 0.808-0.814). In the prognostication task, the traditional MRI metrics correctly predicted patients with CSM who improved at 2-year follow-up on the basis of change in mJOA, with an accuracy of 0.58 (95% CI 0.57-0.58). In comparison, the DTI model performed with an accuracy of 0.62 (95% CI 0.61-0.62) and the DBSI model had an accuracy of 0.72 (95% CI 0.718-0.73). CONCLUSIONS: Conventional MRI is a powerful tool to assess structural abnormality in CSM but is inherently limited in its ability to characterize spinal cord tissue injury. The results of this study demonstrate that advanced imaging techniques, namely DBSI-derived metrics from dMRI, provide granular assessments of spinal cord microstructure that can offer better diagnostic and prognostic utility.

Using Multimodal Assessments to Reevaluate Depression Designations for Spine Surgery Candidates.

BACKGROUND: Depression is common in spine surgery candidates and may influence postoperative outcomes. Ecological momentary assessments (EMAs) can overcome limitations of existing depression screening methods (e.g., recall bias, inaccuracy of historical diagnoses) by longitudinally monitoring depression symptoms in daily life. In this study, we compared EMA-based depression assessment with retrospective self-report (a 9-item Patient Health Questionnaire [PHQ-9]) and chart-based depression diagnosis in lumbar spine surgery candidates. We further examined the associations of each depression assessment method with surgical outcomes. METHODS: Adult patients undergoing lumbar spine surgery (n = 122) completed EMAs quantifying depressive symptoms up to 5 times daily for 3 weeks preoperatively. Correlations (rank-biserial or Spearman) among EMA means, a chart-based depression history, and 1-time preoperative depression surveys (PHQ-9 and Psychache Scale) were analyzed. Confirmatory factor analysis was used to categorize PHQ-9 questions as somatic or non-somatic; subscores were compared with a propensity score-matched general population cohort. The associations of each screening modality with 6-month surgical outcomes (pain, disability, physical function, pain interference) were analyzed with multivariable regression. RESULTS: The association between EMA Depression scores and a depression history was weak (rrb = 0.34 [95% confidence interval (CI), 0.14 to 0.52]). Moderate correlations with EMA-measured depression symptoms were observed for the PHQ-9 (rs = 0.51 [95% CI, 0.37 to 0.63]) and the Psychache Scale (rs = 0.68 [95% CI, 0.57 to 0.76]). Compared with the matched general population cohort, spine surgery candidates endorsed similar non-somatic symptoms but significantly greater somatic symptoms on the PHQ-9. EMA Depression scores had a stronger association with 6-month surgical outcomes than the other depression screening modalities did. CONCLUSIONS: A history of depression in the medical record is not a reliable indication of preoperative depression symptom severity. Cross-sectional depression assessments such as PHQ-9 have stronger associations with daily depression symptoms but may conflate somatic depression symptoms with spine-related disability. As an alternative to these methods, mobile health technology and EMAs provide an opportunity to collect real-time, longitudinal data on depression symptom severity, potentially improving prognostic accuracy. LEVEL OF EVIDENCE: Diagnostic Level III. See Instructions for Authors for a complete description of levels of evidence.

Diffusion MRI Metrics Characterize Postoperative Clinical Outcomes After Surgery for Cervical Spondylotic Myelopathy.

BACKGROUND AND OBJECTIVES: Advanced diffusion-weighted MRI (DWI) modeling, such as diffusion tensor imaging (DTI) and diffusion basis spectrum imaging (DBSI), may help guide rehabilitation strategies after surgical decompression for cervical spondylotic myelopathy (CSM). Currently, however, postoperative DWI is difficult to interpret, owing to signal distortions from spinal instrumentation. Therefore, we examined the relationship between postoperative DTI/DBSI-extracted from the rostral C3 spinal level-and clinical outcome measures at 2-year follow-up after decompressive surgery for CSM. METHODS: Fifty patients with CSM underwent complete clinical and DWI evaluation-followed by DTI/DBSI analysis-at baseline and 2-year follow-up. Clinical outcomes included the modified Japanese Orthopedic Association score and comprehensive patient-reported outcomes. DTI metrics included apparent diffusion coefficient, fractional anisotropy, axial diffusivity, and radial diffusivity. DBSI metrics evaluated white matter tracts through fractional anisotropy, fiber fraction, axial diffusivity, and radial diffusivity as well as extra-axonal pathology through restricted and nonrestricted fraction. Cross-sectional Spearman's correlations were used to compare postoperative DTI/DBSI metrics with clinical outcomes. RESULTS: Twenty-seven patients with CSM, including 15, 7, and 5 with mild, moderate, and severe disease, respectively, possessed complete baseline and postoperative DWI scans. At 2-year follow-up, there were 10 significant correlations among postoperative DBSI metrics and postoperative clinical outcomes compared with 3 among postoperative DTI metrics. Of the 13 significant correlations, 7 involved the neck disability index (NDI). The strongest relationships were between DBSI axial diffusivity and NDI (r = 0.60, P < .001), DBSI fiber fraction and NDI (rs = -0.58, P < .001), and DBSI restricted fraction and NDI (rs = 0.56, P < .001). The weakest correlation was between DTI apparent diffusion coefficient and NDI (r = 0.35, P = .02). CONCLUSION: Quantitative measures of spinal cord microstructure after surgery correlate with postoperative neurofunctional status, quality of life, and pain/disability at 2 years after decompressive surgery for CSM. In particular, DBSI metrics may serve as meaningful biomarkers for postoperative disease severity for patients with CSM.

Preoperative Mobile Health Data Improve Predictions of Recovery From Lumbar Spine Surgery.

BACKGROUND AND OBJECTIVES: Neurosurgeons and hospitals devote tremendous resources to improving recovery from lumbar spine surgery. Current efforts to predict surgical recovery rely on one-time patient report and health record information. However, longitudinal mobile health (mHealth) assessments integrating symptom dynamics from ecological momentary assessment (EMA) and wearable biometric data may capture important influences on recovery. Our objective was to evaluate whether a preoperative mHealth assessment integrating EMA with Fitbit monitoring improved predictions of spine surgery recovery. METHODS: Patients age 21-85 years undergoing lumbar surgery for degenerative disease between 2021 and 2023 were recruited. For up to 3 weeks preoperatively, participants completed EMAs up to 5 times daily asking about momentary pain, disability, depression, and catastrophizing. At the same time, they were passively monitored using Fitbit trackers. Study outcomes were good/excellent recovery on the Quality of Recovery-15 (QOR-15) and a clinically important change in Patient-Reported Outcomes Measurement Information System Pain Interference 1 month postoperatively. After feature engineering, several machine learning prediction models were tested. Prediction performance was measured using the c-statistic. RESULTS: A total of 133 participants were included, with a median (IQR) age of 62 (53, 68) years, and 56% were female. The median (IQR) number of preoperative EMAs completed was 78 (61, 95), and the median (IQR) number of days with usable Fitbit data was 17 (12, 21). 63 patients (48%) achieved a clinically meaningful improvement in Patient-Reported Outcomes Measurement Information System pain interference. Compared with traditional evaluations alone, mHealth evaluations led to a 34% improvement in predictions for pain interference (c = 0.82 vs c = 0.61). 49 patients (40%) had a good or excellent recovery based on the QOR-15. Including preoperative mHealth data led to a 30% improvement in predictions of QOR-15 (c = 0.70 vs c = 0.54). CONCLUSION: Multimodal mHealth evaluations improve predictions of lumbar surgery outcomes. These methods may be useful for informing patient selection and perioperative recovery strategies.

Implications of Preoperative Depression for Lumbar Spine Surgery Outcomes: A Systematic Review and Meta-Analysis.

Importance: Comorbid depression is common among patients with degenerative lumbar spine disease. Although a well-researched topic, the evidence of the role of depression in spine surgery outcomes remains inconclusive. Objective: To investigate the association between preoperative depression and patient-reported outcome measures (PROMs) after lumbar spine surgery. Data Sources: A systematic search of PubMed, Cochrane Database of Systematic Reviews, Embase, Scopus, PsychInfo, Web of Science, and ClinicalTrials.gov was performed from database inception to September 14, 2023. Study Selection: Included studies involved adults undergoing lumbar spine surgery and compared PROMs in patients with vs those without depression. Studies evaluating the correlation between preoperative depression and disease severity were also included. Data Extraction and Synthesis: All data were independently extracted by 2 authors and independently verified by a third author. Study quality was assessed using Newcastle-Ottawa Scale. Random-effects meta-analysis was used to synthesize data, and I2 was used to assess heterogeneity. Metaregression was performed to identify factors explaining the heterogeneity. Main Outcomes and Measures: The primary outcome was the standardized mean difference (SMD) of change from preoperative baseline to postoperative follow-up in PROMs of disability, pain, and physical function for patients with vs without depression. Secondary outcomes were preoperative and postoperative differences in absolute disease severity for these 2 patient populations. Results: Of the 8459 articles identified, 44 were included in the analysis. These studies involved 21 452 patients with a mean (SD) age of 57 (8) years and included 11 747 females (55%). Among these studies, the median (range) follow-up duration was 12 (6-120) months. The pooled estimates of disability, pain, and physical function showed that patients with depression experienced a greater magnitude of improvement compared with patients without depression, but this difference was not significant (SMD, 0.04 [95% CI, -0.02 to 0.10]; I2 = 75%; P = .21). Nonetheless, patients with depression presented with worse preoperative disease severity in disability, pain, and physical function (SMD, -0.52 [95% CI, -0.62 to -0.41]; I2 = 89%; P < .001), which remained worse postoperatively (SMD, -0.52 [95% CI, -0.75 to -0.28]; I2 = 98%; P < .001). There was no significant correlation between depression severity and the primary outcome. A multivariable metaregression analysis suggested that age, sex (male to female ratio), percentage of comorbidities, and follow-up attrition were significant sources of variance. Conclusions and Relevance: Results of this systematic review and meta-analysis suggested that, although patients with depression had worse disease severity both before and after surgery compared with patients without depression, they had significant potential for recovery in disability, pain, and physical function. Further investigations are needed to examine the association between spine-related disability and depression as well as the role of perioperative mental health treatments.