Hypotension requiring vasopressor treatment and increased cardiac complications in elderly spinal cord injury patients: a prospective TRACK-SCI registry study

OBJECTIVE

Increasing life expectancy has led to an older population. In this study, the authors analyzed complications and outcomes in elderly patients following spinal cord injury (SCI) using the established multi-institutional prospective study Transforming Research and Clinical Knowledge in SCI (TRACK-SCI) database collected in the Department of Neurosurgical Surgery at the University of California, San Francisco.

METHODS

TRACK-SCI was queried for elderly individuals (≥ 65 years of age) with traumatic SCI from 2015 to 2019. Primary outcomes of interest included total hospital length of stay, perioperative complications, postoperative complications, and in-hospital mortality. Secondary outcomes included disposition location, and neurological improvement based on the American Spinal Injury Association Impairment Scale (AIS) grade at discharge. Descriptive analysis, Fisher's exact test, univariate analysis, and multivariable regression analysis were performed.

RESULTS

The study cohort consisted of 40 elderly patients. The in-hospital mortality rate was 10%. Every patient in this cohort experienced at least 1 complication, with a mean of 6.6 separate complications (median 6, mode 4). The most common complication categories were cardiovascular, with a mean of 1.6 complications (median 1, mode 1), and pulmonary, with a mean of 1.3 (median 1, mode 0) complications, with 35 patients (87.5%) having at least 1 cardiovascular complication and 25 (62.5%) having at least 1 pulmonary complication. Overall, 32 patients (80%) required vasopressor treatment for mean arterial pressure (MAP) maintenance goals. The use of norepinephrine correlated with increased cardiovascular complications. Only 3 patients (7.5%) of the total cohort had an improved AIS grade compared with their acute level at admission.

CONCLUSIONS

Given the increased frequency of cardiovascular complications associated with vasopressor use in elderly SCI patients, caution is warranted when targeting MAP goals in these patients. A downward adjustment of blood pressure maintenance goals and prophylactic cardiology consultation to select the most appropriate vasopressor agent may be advisable for SCI patients ≥ 65 years of age.

Racial Differences in Postoperative Opioid Prescribing Practices in Spine Surgical Patients

BACKGROUND

As the opioid epidemic accelerates in the United States, numerous sociodemographic factors have been implicated its development and are, furthermore, a driving factor of the disparities in postoperative pain management. Recent studies have suggested potential associations between the influence of race and ethnicity on pain perception but also the presence of unconscious biases in the treatment of pain in minority patients.

OBJECTIVE

To characterize the perioperative opioid requirements across racial groups after spine surgery.

METHODS

A retrospective, observational study of 1944 opioid-naive adult patients undergoing a neurosurgical spine procedure, from June 2012 to December 2019, was performed at a large, quaternary care institute. Postoperative inpatient and outpatient opioid usage was measured by oral morphine equivalents, across various racial groups.

RESULTS

Case characteristics were similar between racial groups. In the postoperative period, White patients had shorter lengths of stay compared with Black and Asian patients ( P < .05). Asian patients used lower postoperative inpatient opioid doses in comparison with White patients ( P < .001). White patients were discharged with significantly higher doses of opioids compared with Black patients ( P < .01); however, they were less likely to be readmitted within 30 days of discharge ( P < .01).

CONCLUSION

In a large cohort of opioid-naive postoperative neurosurgical patients, this study demonstrates higher inpatient and outpatient postoperative opioid usage among White patients. Increasing physician awareness to the effect of race on inpatient and outpatient pain management would allow for a modified opioid prescribing practice that ensures limited yet effective opioid dosages void of implicit biases.

Development of new postoperative neck pain at 12 and 24 months after surgery for cervical spondylotic myelopathy: a Quality Outcomes Database study

OBJECTIVE

Patients who undergo surgery for cervical spondylotic myelopathy (CSM) will occasionally develop postoperative neck pain that was not present preoperatively, yet the incidence of this phenomenon is unclear. The authors aimed to elucidate patient and surgical factors associated with new-onset sustained pain after CSM surgery.

METHODS

The authors reviewed data from the Quality Outcomes Database (QOD) CSM module. The presence of neck pain was defined using the neck pain numeric rating scale (NRS). Patients with no neck pain at baseline (neck NRS score ≤ 1) were then stratified based on the presence of new postoperative pain development (neck NRS score ≥ 2) at 12 and 24 months postoperatively.

RESULTS

Of 1141 patients in the CSM QOD, 224 (19.6%) reported no neck pain at baseline. Among 170 patients with no baseline neck pain and available 12-month follow-up, 46 (27.1%) reported new postoperative pain. Among 184 patients with no baseline neck pain and available 24-month follow-up, 53 (28.8%) reported new postoperative pain. The mean differences in neck NRS scores were 4.3 for those with new postoperative pain compared with those without at 12 months (4.4 ± 2.2 vs 0.1 ± 0.3, p < 0.001) and 3.9 at 24 months (4.1 ± 2.4 vs 0.2 ± 0.4, p < 0.001). The majority of patients reporting new-onset neck pain reported being satisfied with surgery, but their satisfaction was significantly lower compared with patients without pain at the 12-month (66.7% vs 94.3%, p < 0.001) and 24-month (65.4% vs 90.8%, p < 0.001) follow-ups. The baseline Neck Disability Index (NDI) was an independent predictor of new postoperative neck pain at both the 12-month and 24-month time points (adjusted OR [aOR] 1.04, 95% CI 1.01-1.06; p = 0.002; and aOR 1.03, 95% CI 1.01-1.05; p = 0.026, respectively). The total number of levels treated was associated with new-onset neck pain at 12 months (aOR 1.34, 95% CI 1.09-1.64; p = 0.005), and duration of symptoms more than 3 months was a predictor of 24-month neck pain (aOR 3.22, 95% CI 1.01-10.22; p = 0.048).

CONCLUSIONS

Increased NDI at baseline, number of levels treated surgically, and duration of symptoms longer than 3 months preoperatively correlate positively with the risk of new-onset neck pain following CSM surgery. The majority of patients with new-onset neck pain still report satisfaction from surgery, suggesting that the risk of new-onset neck pain should not hinder indicated operations from being performed.

Spinal Deformity Complexity Checklist for Minimally Invasive Surgery: Expert Consensus from the Minimally Invasive International Spine Study Group

BACKGROUND

We developed a spinal deformity complexity checklist (SDCC) to assess the difficulty in performing a circumferential minimally invasive surgery (MIS) for adult spinal deformity.

METHODS

A modified Delphi method of panel experts was used to construct an SDCC checklist of radiographic and patient-related characteristics that could affect the complexity of surgery via MIS approaches. Ten surgeons with expertise in MIS deformity surgery were queried to develop and refine the SDCC with 3 radiographic categories (x-ray, magnetic resonance imaging, computed tomography) and 1 patient-related category. Within each category, characteristics affecting MIS complexity were identified by initial roundtable discussion. Second-round discussion determined which characteristics substantially impacted complexity the most.

RESULTS

Thirteen characteristics within the x-ray category were determined. Spinopelvic characteristics, endpoints of instrumentation, and prior hardware/fusion were associated with increased complexity. Vertebral body rotation-as reflected by the Nash-Moe grade-added significant complexity. Psoas anatomy and spinal stenosis added the most complexity for the 5 magnetic resonance imaging characteristics. There were 3 characteristics in the CT category with pre-exisiting fusion, being the variable most highly selected. Of the 5 patient-related characteristics, osteoporosis and BMI were found to most affect complexity.

CONCLUSIONS

The SDCC is a comprehensive list of pertinent radiographic and patient-related characteristics affecting complexity level for MIS deformity surgery. The value of the SDCC is that it allows rapid assessment of key factors when determining whether MIS surgery can be performed effectively and safely. Patients with scores of 4 in any characteristic should be considered challenging to treat with MIS; open surgery may be a better alternative.

How closely are outcome questionnaires correlated to patient satisfaction after cervical spine surgery for myelopathy?

OBJECTIVE

Patient-reported outcomes (PROs) have become the standard means to measure surgical outcomes. Insurers and policy makers are also increasingly utilizing PROs to assess the value of care and measure different aspects of a patient's condition. For cervical myelopathy, it is currently unclear which outcome measure best reflects patient satisfaction. In this investigation, the authors evaluated patients treated for cervical myelopathy to determine which outcome questionnaires best correlate with patient satisfaction.

METHODS

The Quality Outcomes Database (QOD), a prospectively collected multi-institutional database, was used to retrospectively analyze patients undergoing surgery for cervical myelopathy. The North American Spine Society (NASS) satisfaction index, Neck Disability Index (NDI), numeric rating scales for neck pain (NP-NRS) and arm pain (AP-NRS), EQ-5D, and modified Japanese Orthopaedic Association (mJOA) scale were evaluated.

RESULTS

The analysis included 1141 patients diagnosed with myelopathy, of whom 1099 had an NASS satisfaction index recorded at any of the follow-up time points. Concomitant radiculopathy was an indication for surgery in 368 (33.5%) patients, and severe neck pain (NP-NRS ≥ 7) was present in 471 (42.8%) patients. At the 3-month follow-up, NASS patient satisfaction index scores were positively correlated with scores for the NP-NRS (r = 0.30), AP-NRS (r = 0.32), and NDI (r = 0.36) and negatively correlated with EQ-5D (r = -0.38) and mJOA (r = -0.29) scores (all p < 0.001). At the 12-month follow-up, scores for the NASS index were positively correlated with scores for the NP-NRS (r = 0.44), AP-NRS (r = 0.38), and NDI (r = 0.46) and negatively correlated with scores for the EQ-5D (r = -0.40) and mJOA (r = -0.36) (all p < 0.001). At the 24-month follow-up, NASS index scores were positively correlated with NP-NRS (r = 0.49), AP-NRS (r = 0.36), and NDI (r = 0.49) scores and negatively correlated with EQ-5D (r = -0.44) and mJOA (r = -0.38) scores (all p < 0.001).

CONCLUSIONS

Neck pain was highly prevalent in patients with myelopathy. Notably, improvement in neck pain-associated disability rather than improvement in myelopathy was the most prominent PRO factor for patients. This finding may reflect greater patient concern for active pain symptoms than for neurological symptoms caused by myelopathy. As commercial payers begin to examine novel remuneration strategies for surgical interventions, thoughtful analysis of PRO measurements will have increasing relevance.

Characteristics of patients who return to work after undergoing surgery for cervical spondylotic myelopathy: a Quality Outcomes Database study

OBJECTIVE

Return to work (RTW) is an important surgical outcome for patients who are employed, yet a significant number of patients with cervical spondylotic myelopathy (CSM) who are employed undergo cervical spine surgery and fail to RTW. In this study, the authors investigated factors associated with failure to RTW in the CSM population who underwent cervical spine surgery and who were considered to have a good surgical outcome yet failed to RTW.

METHODS

This study retrospectively analyzed prospectively collected data from the cervical myelopathy module of a national spine registry, the Quality Outcomes Database. The CSM data set of the Quality Outcomes Database was queried for patients who were employed at the time of surgery and planned to RTW postoperatively. Distinct multivariable logistic regression models were fitted with 3-month RTW as an outcome for the overall population to identify risk factors for failure to RTW. Good outcomes were defined as patients who had no adverse events (readmissions or complications), who had achieved 30% improvement in Neck Disability Index score, and who were satisfied (North American Spine Society satisfaction score of 1 or 2) at 3 months postsurgery.

RESULTS

Of the 409 patients who underwent surgery, 80% (n = 327) did RTW at 3 months after surgery. At 3 months, 56.9% of patients met the criteria for a good surgical outcome, and patients with a good outcome were more likely to RTW (88.1% vs 69.2%, p < 0.01). Of patients with a good outcome, 11.9% failed to RTW at 3 months. Risk factors for failing to RTW despite a good outcome included preoperative short-term disability or leave status (OR 3.03 [95% CI 1.66-7.90], p = 0.02); a higher baseline Neck Disability Index score (OR 1.41 [95% CI 1.09-1.84], p < 0.01); and higher neck pain score at 3 months postoperatively (OR 0.81 [95% CI 0.66-0.99], p = 0.04).

CONCLUSIONS

Most patients with CSM who undergo spine surgery reenter the workforce within 3 months from surgery, with RTW rates being higher among patients who experience good outcomes. Among patients with good outcomes who were employed, failure to RTW was associated with being on preoperative short-term disability or leave status prior to surgery as well as higher neck pain scores at baseline and at 3 months postoperatively.

Leveraging machine learning to ascertain the implications of preoperative body mass index on surgical outcomes for 282 patients with preoperative obesity and lumbar spondylolisthesis in the Quality Outcomes Database

OBJECTIVE

Prior studies have revealed that a body mass index (BMI) ≥ 30 is associated with worse outcomes following surgical intervention in grade 1 lumbar spondylolisthesis. Using a machine learning approach, this study aimed to leverage the prospective Quality Outcomes Database (QOD) to identify a BMI threshold for patients undergoing surgical intervention for grade 1 lumbar spondylolisthesis and thus reliably identify optimal surgical candidates among obese patients.

METHODS

Patients with grade 1 lumbar spondylolisthesis and preoperative BMI ≥ 30 from the prospectively collected QOD lumbar spondylolisthesis module were included in this study. A 12-month composite outcome was generated by performing principal components analysis and k-means clustering on four validated measures of surgical outcomes in patients with spondylolisthesis. Random forests were generated to determine the most important preoperative patient characteristics in predicting the composite outcome. Recursive partitioning was used to extract a BMI threshold associated with optimal outcomes.

RESULTS

The average BMI was 35.7, with 282 (46.4%) of the 608 patients from the QOD data set having a BMI ≥ 30. Principal components analysis revealed that the first principal component accounted for 99.2% of the variance in the four outcome measures. Two clusters were identified corresponding to patients with suboptimal outcomes (severe back pain, increased disability, impaired quality of life, and low satisfaction) and to those with optimal outcomes. Recursive partitioning established a BMI threshold of 37.5 after pruning via cross-validation.

CONCLUSIONS

In this multicenter study, the authors found that a BMI ≤ 37.5 was associated with improved patient outcomes following surgical intervention. These findings may help augment predictive analytics to deliver precision medicine and improve prehabilitation strategies.

Wound complications in metastatic spine tumor patients with and without preoperative radiation

OBJECTIVE

Wound complications are a common adverse event following metastatic spine tumor surgery. Some patients with spinal metastases may first undergo radiation but eventually require spinal surgery because of either cord compression or instability. The authors compared wound complication rates in patients who had undergone surgery for metastatic disease and received preoperative radiation treatments, postoperative radiation, or no radiation.

METHODS

Records from patients treated at the University of California, San Francisco, for metastatic spine disease between 2005 and 2017 were retrospectively reviewed. Baseline characteristics were collected, including preoperative Karnofsky Performance Status (KPS), Spine Instability Neoplastic Score, total radiation dose, indication for surgery, diabetes status, time between radiation and surgery, use of perioperative chemotherapy or steroids, estimated blood loss, extent of fusion, and preoperative albumin level. Wound complication was defined as poor healing, dehiscence, or infection per the Centers for Disease Control and Prevention guidelines, within 6 months of surgery. One-way ANOVA was used to compare means across groups. Cumulative incidence analysis with competing risk methodology was used to adjust for risk of death during follow-up. Statistical analysis was performed using R software.

RESULTS

Two hundred five patients with adequate medical records were identified. Seventy patients had received preoperative radiation, 74 had received postoperative radiation within 6 months after surgery, and 61 had received no radiation at the surgical site. Wound complication rates were similar across the 3 cohorts: 14.3% (n = 10) in the group with preoperative radiation, 10.8% (n = 8) in the group that received postoperative radiation, and 11.5% (n = 7) in the group with no radiation (p = 0.773). Competing risk analysis showed a higher cumulative incidence of wound complications for the preoperative cohort, though this difference was not significant (p = 0.46). Overall, 89 patients were treated with external beam radiation therapy (EBRT), whereas 55 received stereotactic body radiation therapy (SBRT). There was no significant difference in wound complications for patients treated with EBRT (11.2%, n = 10) versus SBRT (14.5%, n = 8; p = 0.825). KPS was the only factor correlated with wound complications on univariate analysis (p = 0.03).

CONCLUSIONS

Wound complication rates did not differ across the 3 cohorts: patients treated with preoperative radiation, postoperative radiation within 6 months of surgery, or no radiation. The effect size was small for KPS and likely does not represent a clinically significant predictor of wound complications.

Cervical spondylotic myelopathy with severe axial neck pain: is anterior or posterior approach better?

OBJECTIVE

The aim of this study was to determine whether multilevel anterior cervical discectomy and fusion (ACDF) or posterior cervical laminectomy and fusion (PCLF) is superior for patients with cervical spondylotic myelopathy (CSM) and high preoperative neck pain.

METHODS

This was a retrospective study of prospectively collected data using the Quality Outcomes Database (QOD) CSM module. Patients who received a subaxial fusion of 3 or 4 segments and had a visual analog scale (VAS) neck pain score of 7 or greater at baseline were included. The 3-, 12-, and 24-month outcomes were compared for patients undergoing ACDF with those undergoing PCLF.

RESULTS

Overall, 1141 patients with CSM were included in the database. Of these, 495 (43.4%) presented with severe neck pain (VAS score > 6). After applying inclusion and exclusion criteria, we compared 65 patients (54.6%) undergoing 3- and 4-level ACDF and 54 patients (45.4%) undergoing 3- and 4-level PCLF. Patients undergoing ACDF had worse Neck Disability Index scores at baseline (52.5 ± 15.9 vs 45.9 ± 16.8, p = 0.03) but similar neck pain (p > 0.05). Otherwise, the groups were well matched for the remaining baseline patient-reported outcomes. The rates of 24-month follow-up for ACDF and PCLF were similar (86.2% and 83.3%, respectively). At the 24-month follow-up, both groups demonstrated mean improvements in all outcomes, including neck pain (p < 0.05). In multivariable analyses, there was no significant difference in the degree of neck pain change, rate of neck pain improvement, rate of pain-free achievement, and rate of reaching minimal clinically important difference (MCID) in neck pain between the two groups (adjusted p > 0.05). However, ACDF was associated with a higher 24-month modified Japanese Orthopaedic Association scale (mJOA) score (β = 1.5 [95% CI 0.5-2.6], adjusted p = 0.01), higher EQ-5D score (β = 0.1 [95% CI 0.01-0.2], adjusted p = 0.04), and higher likelihood for return to baseline activities (OR 1.2 [95% CI 1.1-1.4], adjusted p = 0.002).

CONCLUSIONS

Severe neck pain is prevalent among patients undergoing surgery for CSM, affecting more than 40% of patients. Both ACDF and PCLF achieved comparable postoperative neck pain improvement 3, 12, and 24 months following 3- or 4-segment surgery for patients with CSM and severe neck pain. However, multilevel ACDF was associated with superior functional status, quality of life, and return to baseline activities at 24 months in multivariable adjusted analyses.

Minimally invasive versus open transforaminal lumbar interbody fusion for grade I lumbar spondylolisthesis: 5-year follow-up from the prospective multicenter Quality Outcomes Database registry

OBJECTIVE

Minimally invasive transforaminal lumbar interbody fusion (MI-TLIF) has been used to treat degenerative lumbar spondylolisthesis and is associated with expedited recovery, reduced operative blood loss, and shorter hospitalizations compared to those with traditional open TLIF. However, the impact of MI-TLIF on long-term patient-reported outcomes (PROs) is less clear. Here, the authors compare the outcomes of MI-TLIF to those of traditional open TLIF for grade I degenerative lumbar spondylolisthesis at 60 months postoperatively.

METHODS

The authors utilized the prospective Quality Outcomes Database registry and queried for patients with grade I degenerative lumbar spondylolisthesis who had undergone single-segment surgery via an MI or open TLIF method. PROs were compared 60 months postoperatively. The primary outcome was the Oswestry Disability Index (ODI). The secondary outcomes included the numeric rating scale (NRS) for back pain (NRS-BP), NRS for leg pain (NRS-LP), EQ-5D, North American Spine Society (NASS) satisfaction, and cumulative reoperation rate. Multivariable models were constructed to assess the impact of MI-TLIF on PROs, adjusting for variables reaching p < 0.20 on univariable analyses and respective baseline PRO values.

RESULTS

The study included 297 patients, 72 (24.2%) of whom had undergone MI-TLIF and 225 (75.8%) of whom had undergone open TLIF. The 60-month follow-up rates were similar for the two cohorts (86.1% vs 75.6%, respectively; p = 0.06). Patients did not differ significantly at baseline for ODI, NRS-BP, NRS-LP, or EQ-5D (p > 0.05 for all). Perioperatively, MI-TLIF was associated with less blood loss (108.8 ± 85.6 vs 299.6 ± 242.2 ml, p < 0.001) and longer operations (228.2 ± 111.5 vs 189.6 ± 66.5 minutes, p < 0.001) but had similar lengths of hospitalizations (MI-TLIF 2.9 ± 1.8 vs open TLIF 3.3 ± 1.6 days, p = 0.08). Discharge disposition to home or home health was similar (MI-TLIF 93.1% vs open TLIF 91.1%, p = 0.60). Both cohorts improved significantly from baseline for the 60-month ODI, NRS-BP, NRS-LP, and EQ-5D (p < 0.001 for all comparisons). In adjusted analyses, MI-TLIF, compared to open TLIF, was associated with similar 60-month ODI, ODI change, odds of reaching ODI minimum clinically important difference, NRS-BP, NRS-BP change, NRS-LP, NRS-LP change, EQ-5D, EQ-5D change, and NASS satisfaction (adjusted p > 0.05 for all). The 60-month reoperation rates did not differ significantly (MI-TLIF 5.6% vs open TLIF 11.6%, p = 0.14).

CONCLUSIONS

For symptomatic, single-level grade I degenerative lumbar spondylolisthesis, MI-TLIF was associated with decreased blood loss perioperatively, but there was no difference in 60-month outcomes for disability, back pain, leg pain, quality of life, or satisfaction between MI and open TLIF. There was no difference in cumulative reoperation rates between the two procedures. These results suggest that in appropriately selected patients, either procedure may be employed depending on patient and surgeon preferences.

Posterior-based resection of spinal meningiomas: an institutional experience of 141 patients with an average of 28 months of follow-up

OBJECTIVE

Spinal meningiomas pose unique challenges based on the location of their dural attachment. However, there is a paucity of literature investigating the role of dural attachment location on outcomes after posterior-based approach for spinal meningioma resection. The aim of this study was to investigate any differences in outcomes between dural attachment location subgroups in spinal meningioma patients who underwent posterior-based resection.

METHODS

This was a single-institution review of patients who underwent resection of a spinal meningioma from 1997 to 2017. Surgical, oncological, and neurological outcomes were compared between patients with varying dural attachments. Multivariate analysis was utilized.

RESULTS

A total of 141 patients were identified. The mean age was 62 years, and 110 women were included. The sites of dural attachments were as follows: 16 (11.3%) dorsal, 31 (22.0%) dorsolateral, 17 (12.1%) lateral, 40 (28.4%) ventral, and 37 (26.2%) ventrolateral. Most meningiomas were WHO grade I (92.2%) and in the thoracic spine (61.0%). All patients underwent a posterior approach for tumor resection. There were no differences between subgroups in terms of largest diameter of tumor resected (p = 0.201), gross-total resection (GTR) or subtotal resection (p = 0.362), Simpson grade of resection, perioperative complications (p = 0.116), long-term neurological deficit (p = 0.100), or postoperative radiation therapy (p = 0.971). Cervical spine location was associated with reduced incidence of GTR (OR 0.271, 95% CI 0.108-0.684, p = 0.006) on multivariate analysis. The overall incidence of recurrence/progression was 4.6%, with no difference (p = 0.800) between subgroups. Similarly, the average length of follow-up was 28.1 months, with no difference between subgroups (p = 0.413).

CONCLUSIONS

Posterior-based approaches for resection of spinal meningiomas are safe and effective, regardless of dural attachment location, with similar surgical, oncological, and neurological outcomes. Comparison of long-term recurrence rates between dural attachment subgroups is required.

Realistic long-term dysphagia rates after anterior cervical discectomy with fusion: is there a correlation with postoperative sagittal alignment and lordosis at a minimum 2-year follow-up?

OBJECTIVE

Postoperative dysphagia after anterior cervical discectomy and fusion (ACDF) has many contributing factors, and long-term data are sparse. The authors evaluated dysphagia after ACDF based on levels fused and cervical sagittal parameters.

METHODS

Patients who underwent ACDF between 2009 and 2018 at the University of California, San Francisco (UCSF), were retrospectively studied. Dysphagia was evaluated preoperatively, immediately postoperatively, and at last follow-up using the UCSF dysphagia score. Dysphagia was categorized as normal (level 7), mild (levels 5 and 6), moderate (levels 3 and 4), and severe (levels 1 and 2). The UCSF mild dysphagia score was further classified as "minimal dysphagia," while moderate and severe dysphagia were classified as "significant dysphagia." "Any dysphagia" included any dysphagia, regardless of grade. Cervical sagittal parameters were measured preoperatively, immediately postoperatively, and at last follow-up.

RESULTS

A total of 131 patients met inclusion criteria. The mean follow-up was 43.89 (24-142) months. Seventy-eight patients (59.5%) reported dysphagia immediately postoperatively, and 44 patients (33.6%) reported some dysphagia at last follow-up (p < 0.001). The rates of moderate dysphagia were 13.0% immediately postoperatively and 1.5% at the last follow-up (p < 0.001). Twenty-two patients (16.8%) had significant dysphagia immediately postoperatively, and 2 patients (1.5%) had significant dysphagia at last follow-up (p < 0.001). Patients with immediate postoperative dysphagia had less C2-7 preoperative lordosis (-9.35°) compared with patients without (-14.15°, p = 0.029), but there was no association between C2-7 lordosis and dysphagia at last follow-up (p = 0.232). The prevalence rates of immediate postoperative dysphagia and long-term dysphagia were 87.5% and 58.3% in ≥ 3-level ACDF; 64.0% and 40.0% in 2-level ACDF; and 43.9% and 17.5% in 1-level ACDF, respectively (p < 0.001).

CONCLUSIONS

The realistic incidence of any dysphagia after ACDF was 59.5% immediately postoperatively and 33.6% at the minimum 2-year follow-up, higher than previously published rates. However, most dysphagia was not severe. The number of fused levels was the most important risk factor for long-term dysphagia, but not for immediate postoperative dysphagia. Loss of preoperative C2-7 lordosis was associated with immediate postoperative dysphagia, but not long-term dysphagia. ACDF segmental lordosis and cervical sagittal vertical axis were not associated with long-term dysphagia in ACDF.

Determining the time frame of maximum clinical improvement in surgical decompression for cervical spondylotic myelopathy when stratified by preoperative myelopathy severity: a cervical Quality Outcomes Database study

OBJECTIVE

While surgical decompression is an important treatment modality for cervical spondylotic myelopathy (CSM), it remains unclear if the severity of preoperative myelopathy status affects potential benefit from surgical intervention and when maximum postoperative improvement is expected. This investigation sought to determine if retrospective analysis of prospectively collected patient-reported outcomes (PROs) following surgery for CSM differed when stratified by preoperative myelopathy status. Secondary objectives included assessment of the minimal clinically important difference (MCID).

METHODS

A total of 1151 patients with CSM were prospectively enrolled from the Quality Outcomes Database at 14 US hospitals. Baseline demographics and PROs at baseline and 3 and 12 months were measured. These included the modified Japanese Orthopaedic Association (mJOA) score, Neck Disability Index (NDI), quality-adjusted life-years (QALYs) from the EQ-5D, and visual analog scale from the EQ-5D (EQ-VAS). Patients were stratified by preoperative myelopathy severity using criteria established by the AO Spine study group: mild (mJOA score 15-17), moderate (mJOA score 12-14), or severe (mJOA score < 12). Univariate analysis was used to identify demographic variables that significantly varied between myelopathy groups. Then, multivariate linear regression and linear mixed regression were used to model the effect of severity and time on PROs, respectively.

RESULTS

For NDI, EQ-VAS, and QALY, patients in all myelopathy cohorts achieved significant, maximal improvement at 3 months without further improvement at 12 months. For mJOA, moderate and severe myelopathy groups demonstrated significant, maximal improvement at 3 months, without further improvement at 12 months. The mild myelopathy group did not demonstrate significant change in mJOA score but did maintain and achieve higher PRO scores overall when compared with more advanced myelopathy cohorts. The MCID threshold was reached in all myelopathy cohorts at 3 months for mJOA, NDI, EQ-VAS, and QALY, with the only exception being mild myelopathy QALY at 3 months.

CONCLUSIONS

As assessed by statistical regression and MCID analysis, patients with cervical myelopathy experience maximal improvement in their quality of life, neck disability, myelopathy score, and overall health by 3 months after surgical decompression, regardless of their baseline myelopathy severity. An exception was seen for the mJOA score in the mild myelopathy cohort, improvement of which may have been limited by ceiling effect. The data presented here will aid surgeons in patient selection, preoperative counseling, and expected postoperative time courses.

Adjacent Segment Vertebral Body Bone Density Changes as Measured By Hounsfield Units After Lumbar Spine Fusion

OBJECTIVE

We sought to evaluate Hounsfield units (HU) at the adjacent segment after single-level transforaminal lumbar interbody fusion (TLIF) with preoperative and postoperative computed tomography scans.

METHODS

We performed a retrospective study on a series of patients who underwent L4-5 TLIF, from 2007 to 2017, by 3 spine surgeons at our institution. One-hundred and forty-three total patients were identified, and 41 patients with minimum 1-year follow-up met inclusion criteria. HU values were measured on preoperative and postoperative computed tomography at the adjacent L3 segment and at L1 as a control arm. Lumbar lordosis, pelvic tilt, pelvic incidence, sacral slope, and sagittal vertical axis were also collected preoperatively and postoperatively.

RESULTS

Mean preoperative HU value at L3 did not differ from the postoperative value (134.11 ± 47.14 mg/cm³ vs. 141.21 ± 55.14 mg/cm³, P = 0.34). Similarly, the mean preoperative HU value at the L1 control level region of interest did not differ from the postoperative value (150.17 ± 53.91 mg/cm³ vs. 145.78 ± 58.34 mg/cm³, P = 0.634). The interrater reliability of HU measurements was satisfactory with a resulting intraclass correlation coefficient of 0.76.

CONCLUSIONS

As measured by HU, we did not observe a change in bone density or other signs of adjacent segment disease at the L3 vertebral body 12 months after L4-5 TLIF. Spinopelvic parameters were not shown to be correlated with HU changes.

Outpatient versus inpatient lumbar decompression surgery: a matched noninferiority study investigating clinical and patient-reported outcomes

OBJECTIVE

Spine surgery represents an ideal target for healthcare cost reduction efforts, with outpatient surgery resulting in significant cost savings. With an increased focus on value-based healthcare delivery, lumbar decompression surgery has been increasingly performed in the outpatient setting when appropriate. The aim of this study was to compare clinical and patient-reported outcomes following outpatient and inpatient lumbar decompression surgery.

METHODS

The Quality Outcomes Database (QOD) was queried for patients undergoing elective one- or two-level lumbar decompression (laminectomy or laminotomy with or without discectomy) for degenerative spine disease. Patients were grouped as outpatient if they had a length of stay (LOS) < 24 hours and as inpatient if they stayed in the hospital ≥ 24 hours. Patients with ≥ 72-hour stay were excluded from the comparative analysis to increase baseline comparability between the two groups. To create two highly homogeneous groups, optimal matching was performed at a 1:1 ratio between the two groups on 38 baseline variables, including demographics, comorbidities, symptoms, patient-reported scores, indications, and operative details. Outcomes of interest were readmissions and reoperations at 30 days and 3 months after surgery, overall satisfaction, and decrease in Oswestry Disability Index (ODI), back pain, and leg pain at 3 months after surgery. Satisfaction was defined as a score of 1 or 2 in the North American Spine Society patient satisfaction index. Noninferiority of outpatient compared with inpatient surgery was defined as risk difference of < 1.5% at a one-sided 97.5% confidence interval.

RESULTS

A total of 18,689 eligible one- and two-level decompression surgeries were identified. The matched study cohorts consisted of 5016 patients in each group. Nonroutine discharge was slightly less common in the outpatient group (0.6% vs 0.3%, p = 0.01). The 30-day readmission rates were 4.4% and 4.3% for the outpatient and inpatient groups, respectively, while the 30-day reoperation rates were 1.4% and 1.5%. The 3-month readmission rates were 6.3% for both groups, and the 3-month reoperation rates were 3.1% for the outpatient cases and 2.9% for the inpatient cases. Overall satisfaction at 3 months was 88.8% for the outpatient group and 88.4% for the inpatient group. Noninferiority of outpatient surgery was documented for readmissions, reoperations, and patient-reported satisfaction from surgery.

CONCLUSIONS

Outpatient lumbar decompression surgery demonstrated slightly lower nonroutine discharge rates in comparison with inpatient surgery. Noninferiority in clinical outcomes at 30 days and 3 months after surgery was documented for outpatient compared with inpatient decompression surgery. Additionally, outpatient decompression surgery performed noninferiorly to inpatient surgery in achieving patient satisfaction from surgery.

Do social determinants of health impact access to neurosurgical care in the United States? A workforce perspective

OBJECTIVE

This study attempts to use neurosurgical workforce distribution to uncover the social determinants of health that are associated with disparate access to neurosurgical care.

METHODS

Data were compiled from public sources and aggregated at the county level. Socioeconomic data were provided by the Brookings Institute. Racial and ethnicity data were gathered from the Centers for Disease Control and Prevention Wide-ranging Online Data for Epidemiologic Research. Physician density was retrieved from the Health Resources and Services Administration Area Health Resources Files. Catchment areas were constructed based on the 628 counties with neurosurgical coverage, with counties lacking neurosurgical coverage being integrated with the nearest covered county based on distances from the National Bureau of Economic Research's County Distance Database. Catchment areas form a mutually exclusive and collectively exhaustive breakdown of the entire US population and licensed neurosurgeons. Socioeconomic factors, race, and ethnicity were chosen as independent variables for analysis. Characteristics for each catchment area were calculated as the population-weighted average across all contained counties. Linear regression analysis modeled two outcomes of interest: neurosurgeon density per capita and average distance to neurosurgical care. Coefficient estimates (CEs) and 95% confidence intervals were calculated and scaled by 1 SD to allow for comparison between variables.

RESULTS

Catchment areas with higher poverty (CE = 0.64, 95% CI 0.34-0.93) and higher prime age employment (CE = 0.58, 95% CI 0.40-0.76) were significantly associated with greater neurosurgeon density. Among categories of race and ethnicity, catchment areas with higher proportions of Black residents (CE = 0.21, 95% CI 0.06-0.35) were associated with greater neurosurgeon density. Meanwhile, catchment areas with higher proportions of Hispanic residents displayed lower neurosurgeon density (CE = -0.17, 95% CI -0.30 to -0.03). Residents of catchment areas with higher housing vacancy rates (CE = 2.37, 95% CI 1.31-3.43), higher proportions of Native American residents (CE = 4.97, 95% CI 3.99-5.95), and higher proportions of Hispanic residents (CE = 2.31, 95% CI 1.26-3.37) must travel farther, on average, to receive neurosurgical care, whereas people living in areas with a lower income (CE = -2.28, 95% CI -4.48 to -0.09) or higher proportion of Black residents (CE = -3.81, 95% CI -4.93 to -2.68) travel a shorter distance.

CONCLUSIONS

Multiple factors demonstrate a significant correlation with neurosurgical workforce distribution in the US, most notably with Hispanic and Native American populations being associated with greater distances to care. Additionally, higher proportions of Hispanic residents correlated with fewer neurosurgeons per capita. These findings highlight the interwoven associations among socioeconomics, race, ethnicity, and access to neurosurgical care nationwide.

Differences in postoperative quality of life in young, early elderly, and late elderly patients undergoing surgical treatment for degenerative cervical myelopathy

OBJECTIVE

Cervical spondylotic myelopathy (CSM) is a common progressive spine disorder affecting predominantly middle-aged and elderly populations. With increasing life expectancy, the incidence of CSM is expected to rise further. The outcomes of elderly patients undergoing CSM surgery and especially their quality of life (QOL) postoperatively remain undetermined. This study retrospectively reviewed patients to identify baseline differences and validated postoperative patient-reported outcome (PRO) measures in elderly patients undergoing CSM surgery.

METHODS

The multi-institutional, neurosurgery-specific NeuroPoint Quality Outcomes Database was queried to identify CSM patients treated surgically at the 14 highest-volume sites from January 2016 to December 2018. Patients were divided into three groups: young (< 65 years), early elderly (65-74 years), and late elderly (≥ 75 years). Demographic and PRO measures (Neck Disability Index [NDI] score, modified Japanese Orthopaedic Association [mJOA] score, EQ-5D score, EQ-5D visual analog scale [VAS] score, arm pain VAS, and neck pain VAS) were compared among the groups at baseline and 3 and 12 months postoperatively.

RESULTS

A total of 1151 patients were identified: 691 patients (60%) in the young, 331 patients (28.7%) in the early elderly, and 129 patients (11.2%) in the late elderly groups. At baseline, younger patients presented with worse NDI scores (p < 0.001) and lower EQ-5D VAS (p = 0.004) and EQ-5D (p < 0.001) scores compared with early and late elderly patients. No differences among age groups were found in the mJOA score. An improvement of all QOL scores was noted in all age groups. On unadjusted analysis at 3 months, younger patients had greater improvement in arm pain VAS, NDI, and EQ-5D VAS compared with early and late elderly patients. At 12 months, the same changes were seen, but on adjusted analysis, there were no differences in PROs between the age groups.

CONCLUSIONS

The authors' results indicate that elderly patients undergoing CSM surgery achieved QOL outcomes that were equivalent to those of younger patients at the 12-month follow-up.

Neurosurgery Subspecialty Practice During a Pandemic: A Multicenter Analysis of Operative Practice in 7 U.S. Neurosurgery Departments During Coronavirus Disease 2019

OBJECTIVE

Changes to neurosurgical practices during the coronavirus disease 2019 (COVID-19) pandemic have not been thoroughly analyzed. We report the effects of operative restrictions imposed under variable local COVID-19 infection rates and health care policies using a retrospective multicenter cohort study and highlight shifts in operative volumes and subspecialty practice.

METHODS

Seven academic neurosurgery departments' neurosurgical case logs were collected; procedures in April 2020 (COVID-19 surge) and April 2019 (historical control) were analyzed overall and by 6 subspecialties. Patient acuity, surgical scheduling policies, and local surge levels were assessed.

RESULTS

Operative volume during the COVID-19 surge decreased 58.5% from the previous year (602 vs. 1449, P = 0.001). COVID-19 infection rates within departments' counties correlated with decreased operative volume (r = 0.695, P = 0.04) and increased patient categorical acuity (P = 0.001). Spine procedure volume decreased by 63.9% (220 vs. 609, P = 0.002), for a significantly smaller proportion of overall practice during the COVID-19 surge (36.5%) versus the control period (42.0%) (P = 0.02). Vascular volume decreased by 39.5% (72 vs. 119, P = 0.01) but increased as a percentage of caseload (8.2% in 2019 vs. 12.0% in 2020, P = 0.04). Neuro-oncology procedure volume decreased by 45.5% (174 vs. 318, P = 0.04) but maintained a consistent proportion of all neurosurgeries (28.9% in 2020 vs. 21.9% in 2019, P = 0.09). Functional neurosurgery volume, which declined by 81.4% (41 vs. 220, P = 0.008), represented only 6.8% of cases during the pandemic versus 15.2% in 2019 (P = 0.02).

CONCLUSIONS

Operative restrictions during the COVID-19 surge led to distinct shifts in neurosurgical practice, and local infective burden played a significant role in operative volume and patient acuity.

Role of obesity in less radiographic correction and worse health-related quality-of-life outcomes following minimally invasive deformity surgery

OBJECTIVE

Minimally invasive surgery (MIS) for adult spinal deformity (ASD) can offer deformity correction with less tissue manipulation and damage. However, the impact of obesity on clinical outcomes and radiographic correction following MIS for ASD is poorly understood. The goal of this study was to determine the role, if any, that obesity has on radiographic correction and health-related quality-of-life measures in MIS for ASD.

METHODS

Data were collected from a multicenter database of MIS for ASD. This was a retrospective review of a prospectively collected database. Patient inclusion criteria were age ≥ 18 years and coronal Cobb angle ≥ 20°, pelvic incidence-lumbar lordosis mismatch ≥ 10°, or sagittal vertical axis (SVA) > 5 cm. A group of patients with body mass index (BMI) < 30 kg/m2 was the control cohort; BMI ≥ 30 kg/m2 was used to define obesity. Obesity cohorts were categorized into BMI 30-34.99 and BMI ≥ 35. All patients had at least 1 year of follow-up. Preoperative and postoperative health-related quality-of-life measures and radiographic parameters, as well as complications, were compared via statistical analysis.

RESULTS

A total of 106 patients were available for analysis (69 control, 17 in the BMI 30-34.99 group, and 20 in the BMI ≥ 35 group). The average BMI was 25.24 kg/m2 for the control group versus 32.46 kg/m2 (p < 0.001) and 39.5 kg/m2 (p < 0.001) for the obese groups. Preoperatively, the BMI 30-34.99 group had significantly more prior spine surgery (70.6% vs 42%, p = 0.04) and worse preoperative numeric rating scale leg scores (7.71 vs 5.08, p = 0.001). Postoperatively, the BMI 30-34.99 cohort had worse Oswestry Disability Index scores (33.86 vs 23.55, p = 0.028), greater improvement in numeric rating scale leg scores (-4.88 vs -2.71, p = 0.012), and worse SVA (51.34 vs 26.98, p = 0.042) at 1 year postoperatively. Preoperatively, the BMI ≥ 35 cohort had significantly worse frailty (4.5 vs 3.27, p = 0.001), Oswestry Disability Index scores (52.9 vs 44.83, p = 0.017), and T1 pelvic angle (26.82 vs 20.71, p = 0.038). Postoperatively, after controlling for differences in frailty, the BMI ≥ 35 cohort had significantly less improvement in their Scoliosis Research Society-22 outcomes questionnaire scores (0.603 vs 1.05, p = 0.025), higher SVA (64.71 vs 25.33, p = 0.015) and T1 pelvic angle (22.76 vs 15.48, p = 0.029), and less change in maximum Cobb angle (-3.93 vs -10.71, p = 0.034) at 1 year. The BMI 30-34.99 cohort had significantly more infections (11.8% vs 0%, p = 0.004). The BMI ≥ 35 cohort had significantly more implant complications (30% vs 11.8%, p = 0.014) and revision surgery within 90 days (5% vs 1.4%, p = 0.034).

CONCLUSIONS

Obese patients who undergo MIS for ASD have less correction of their deformity, worse quality-of-life outcomes, more implant complications and infections, and an increased rate of revision surgery compared with their nonobese counterparts, although both groups benefit from surgery. Appropriate counseling should be provided to obese patients.

Is the Centers for Medicare and Medicaid Services Hierarchical Condition Category Risk Adjustment Model Satisfactory for Quantifying Risk After Spine Surgery?

BACKGROUND

The Centers for Medicare and Medicaid Services (CMS) hierarchical condition category (HCC) coding is a risk adjustment model that allows for the estimation of risk-and cost-associated with health care provision. Current models may not include key factors that fully delineate the risk associated with spine surgery.

OBJECTIVE

To augment CMS HCC risk adjustment methodology with socioeconomic data to improve its predictive capabilities for spine surgery.

METHODS

The National Inpatient Sample was queried for spinal fusion, and the data was merged with county-level coverage and socioeconomic status variables obtained from the Brookings Institute. We predicted outcomes (death, nonroutine discharge, length of stay [LOS], total charges, and perioperative complication) with pairs of hierarchical, mixed effects logistic regression models-one using CMS HCC score alone and another augmenting CMS HCC scores with demographic and socioeconomic status variables. Models were compared using receiver operating characteristic curves. Variable importance was assessed in conjunction with Wald testing for model optimization.

RESULTS

We analyzed 653 815 patients. Expanded models outperformed models using CMS HCC score alone for mortality, nonroutine discharge, LOS, total charges, and complications. For expanded models, variable importance analyses demonstrated that CMS HCC score was of chief importance for models of mortality, LOS, total charges, and complications. For the model of nonroutine discharge, age was the most important variable. For the model of total charges, unemployment rate was nearly as important as CMS HCC score.

CONCLUSION

The addition of key demographic and socioeconomic characteristics substantially improves the CMS HCC risk-adjustment models when modeling spinal fusion outcomes. This finding may have important implications for payers, hospitals, and policymakers.

Short segment rib resection to mitigate risk of pleural violation during retropleural lateral thoracic interbody fusion

It can be difficult to avoid violating the pleura during the retropleural approach to the thoracolumbar spine. In this video, the authors resect a short segment of rib to allow more room for pleural dissection during a minimally invasive (MIS) lateral retropleural approach. After a lateral MIS skin incision, the rib is dissected and removed, clearly identifying the retropleural space. The curvature of the rib can then be followed, decreasing the risk of pleural violation. The pleura can then be mobilized ventrally until the spine is accessed. Managing the diaphragm is also illustrated by separating the fibers without a traditional cut through the muscle. The video can be found here: https://stream.cadmore.media/r10.3171/2022.3.FOCVID21138.

Social risk factors predicting outcomes of cervical myelopathy surgery

OBJECTIVE

Combinations of certain social risk factors of race, sex, education, socioeconomic status (SES), insurance, education, employment, and one's housing situation have been associated with poorer pain and disability outcomes after lumbar spine surgery. To date, an exploration of such factors in patients with cervical spine surgery has not been conducted. The objective of the current work was to 1) define the social risk phenotypes of individuals who have undergone cervical spine surgery for myelopathy and 2) analyze their predictive capacity toward disability, pain, quality of life, and patient satisfaction-based outcomes.

METHODS

The Cervical Myelopathy Quality Outcomes Database was queried for the period from January 2016 to December 2018. Race/ethnicity, educational attainment, SES, insurance payer, and employment status were modeled into unique social phenotypes using latent class analyses. Proportions of social groups were analyzed for demonstrating a minimal clinically important difference (MCID) of 30% from baseline for disability, neck and arm pain, quality of life, and patient satisfaction at the 3-month and 1-year follow-ups.

RESULTS

A total of 730 individuals who had undergone cervical myelopathy surgery were included in the final cohort. Latent class analysis identified 2 subgroups: 1) high risk (non-White race and ethnicity, lower educational attainment, not working, poor insurance, and predominantly lower SES), n = 268, 36.7% (class 1); and 2) low risk (White, employed with good insurance, and higher education and SES), n = 462, 63.3% (class 2). For both 3-month and 1-year outcomes, the high-risk group (class 1) had decreased odds (all p < 0.05) of attaining an MCID score in disability, neck/arm pain, and health-related quality of life. Being in the low-risk group (class 2) resulted in an increased odds of attaining an MCID score in disability, neck/arm pain, and health-related quality of life. Neither group had increased or decreased odds of being satisfied with surgery.

CONCLUSIONS

Although 2 groups underwent similar surgical approaches, the social phenotype involving non-White race/ethnicity, poor insurance, lower SES, and poor employment did not meet MCIDs for a variety of outcome measures. This finding should prompt surgeons to proactively incorporate socially conscience care pathways within healthcare systems, as well as to optimize community-based resources to improve outcomes and personalize care for populations at social risk.

High-impact chronic pain transition in surgical recipients with cervical spondylotic myelopathy

OBJECTIVE

High-impact chronic pain (HICP) is a recently proposed metric that indicates the presence of a severe and troubling pain-related condition. Surgery for cervical spondylotic myelopathy (CSM) is designed to halt disease transition independent of chronic pain status. To date, the prevalence of HICP in individuals with CSM and their HICP transition from presurgery is unexplored. The authors sought to define HICP prevalence, transition, and outcomes in patients with CSM who underwent surgery and identify predictors of these HICP transition groups.

METHODS

CSM surgical recipients were categorized as HICP at presurgery and 3 months if they exhibited pain that lasted 6-12 months or longer with at least one major activity restriction. HICP transition groups were categorized and evaluated for outcomes. Multivariate multinomial modeling was used to predict HICP transition categorization.

RESULTS

A majority (56.1%) of individuals exhibited HICP preoperatively; this value declined to 15.9% at 3 months (71.6% reduction). The presence of HICP was also reflective of other self-reported outcomes at 3 and 12 months, as most demonstrated notable improvement. Higher severity in all categories of self-reported outcomes was related to a continued HICP condition at 3 months. Both social and biological factors predicted HICP translation, with social factors being predominant in transitioning to HICP (from none preoperatively).

CONCLUSIONS

Many individuals who received CSM surgery changed HICP status at 3 months. In a surgical population where decisions are based on disease progression, most of the changed status went from HICP preoperatively to none at 3 months. Both social and biological risk factors predicted HICP transition assignment.

Minimally invasive versus open lumbar spinal fusion: a matched study investigating patient-reported and surgical outcomes

OBJECTIVE

With the expanding indications for and increasing popularity of minimally invasive surgery (MIS) for lumbar spinal fusion, large-scale outcomes analysis to compare MIS approaches with open procedures is warranted.

METHODS

The authors queried the Quality Outcomes Database for patients who underwent elective lumbar fusion for degenerative spine disease. They performed optimal matching, at a 1:2 ratio between patients who underwent MIS and those who underwent open lumbar fusion, to create two highly homogeneous groups in terms of 33 baseline variables (including demographic characteristics, comorbidities, symptoms, patient-reported scores, indications, and operative details). The outcomes of interest were overall satisfaction, decrease in Oswestry Disability Index (ODI), and back and leg pain, as well as hospital length of stay (LOS), operative time, reoperations, and incidental durotomy rate. Satisfaction was defined as a score of 1 or 2 on the North American Spine Society scale. Minimal clinically important difference (MCID) in ODI was defined as ≥ 30% decrease from baseline. Outcomes were assessed at the 3- and 12-month follow-up evaluations.

RESULTS

After the groups were matched, the MIS and open groups consisted of 1483 and 2966 patients, respectively. Patients who underwent MIS fusion had higher odds of satisfaction at 3 months (OR 1.4, p = 0.004); no difference was demonstrated at 12 months (OR 1.04, p = 0.67). Lumbar stenosis, single-level fusion, higher American Society of Anesthesiologists Physical Status Classification System grade, and absence of spondylolisthesis were most prominently associated with higher odds of satisfaction with MIS compared with open surgery. Patients in the MIS group had slightly lower ODI scores at 3 months (mean difference 1.61, p = 0.006; MCID OR 1.14, p = 0.0495) and 12 months (mean difference 2.35, p < 0.001; MCID OR 1.29, p < 0.001). MIS was also associated with a greater decrease in leg and back pain at both follow-up time points. The two groups did not differ in operative time and incidental durotomy rate; however, LOS was shorter for the MIS group. Revision surgery at 12 months was less likely for patients who underwent MIS (4.1% vs 5.6%, p = 0.032).

CONCLUSIONS

In patients who underwent lumbar fusion for degenerative spinal disease, MIS was associated with higher odds of satisfaction at 3 months postoperatively. No difference was demonstrated at the 12-month follow-up. MIS maintained a small, yet consistent, superiority in decreasing ODI and back and leg pain, and MIS was associated with a lower reoperation rate.

An updated management algorithm for incorporating minimally invasive techniques to treat thoracolumbar trauma

OBJECTIVE

Minimally invasive surgery (MIS) techniques can effectively stabilize and decompress many thoracolumbar injuries with decreased morbidity and tissue destruction compared with open approaches. Nonetheless, there is limited direction regarding the breadth and limitations of MIS techniques for thoracolumbar injuries. Consequently, the objectives of this study were to 1) identify the range of current practice patterns for thoracolumbar trauma and 2) integrate expert opinion and literature review to develop an updated treatment algorithm.

METHODS

A survey describing 10 clinical cases with a range of thoracolumbar injuries was sent to 12 surgeons with expertise in spine trauma. The survey results were summarized using descriptive statistics, along with the Fleiss kappa statistic of interrater agreement. To develop an updated treatment algorithm, the authors used a modified Delphi technique that incorporated a literature review, the survey results, and iterative feedback from a group of 14 spine trauma experts. The final algorithm represented the consensus opinion of that expert group.

RESULTS

Eleven of 12 surgeons contacted completed the case survey, including 8 (73%) neurosurgeons and 3 (27%) orthopedic surgeons. For the 4 cases involving patients with neurological deficits, nearly all respondents recommended decompression and fusion, and the proportion recommending open surgery ranged from 55% to 100% by case. Recommendations for the remaining cases were heterogeneous. Among the neurologically intact patients, MIS techniques were typically recommended more often than open techniques. The overall interrater agreement in recommendations was 0.23, indicating fair agreement. Considering both literature review and expert opinion, the updated algorithm indicated that MIS techniques could be used to treat most thoracolumbar injuries. Among neurologically intact patients, percutaneous instrumentation without arthrodesis was recommended for those with AO Spine Thoracolumbar Classification System subtype A3/A4 (Thoracolumbar Injury Classification and Severity Score [TLICS] 4) injuries, but MIS posterior arthrodesis was recommended for most patients with AO Spine subtype B2/B3 (TLICS > 4) injuries. Depending on vertebral body integrity, anterolateral corpectomy or mini-open decompression could be used for patients with neurological deficits.

CONCLUSIONS

Spine trauma experts endorsed a range of strategies for treating thoracolumbar injuries but felt that MIS techniques were an option for most patients. The updated treatment algorithm may provide a foundation for surgeons interested in safe approaches for using MIS techniques to treat thoracolumbar trauma.

Differences in Patient-Reported Outcomes Between Anterior and Posterior Approaches for Treatment of Cervical Spondylotic Myelopathy: A Quality Outcomes Database Analysis

OBJECTIVE

Surgery for cervical spondylotic myelopathy (CSM) may use anterior or posterior approaches. Our objective was to compare baseline differences and validated postoperative patient-reported outcome measures between anterior and posterior approaches.

METHODS

The NeuroPoint Quality Outcomes Database was queried retrospectively to identify patients with symptomatic CSM treated at 14 high-volume sites. Demographic, comorbidity, socioeconomic, and outcome measures were compared between treatment groups at baseline and 3 and 12 months postoperatively.

RESULTS

Of the 1151 patients with CSM in the cervical registry, 791 (68.7%) underwent anterior surgery and 360 (31.3%) underwent posterior surgery. Significant baseline differences were observed in age, comorbidities, myelopathy severity, unemployment, and length of hospital stay. After adjusting for these differences, anterior surgery patients had significantly lower Neck Disability Index score (NDI) and a higher proportion reaching a minimal clinically important difference (MCID) in NDI (P = 0.005 at 3 months; P = 0.003 at 12 months). Although modified Japanese Orthopaedic Association scores were lower in anterior surgery patients at 3 and 12 months (P < 0.001 and P = 0.022, respectively), no differences were seen in MCID or change from baseline. Greater EuroQol-5D improvement at 3 months after anterior versus posterior surgery (P = 0.024) was not sustained at 12 months and was insignificant on multivariate analysis.

CONCLUSIONS

In the largest analysis to date of CSM surgery data, significant baseline differences existed for patients undergoing anterior versus posterior surgery for CSM. After adjusting for these differences, patients undergoing anterior surgery were more likely to achieve clinically significant improvement in NDI at short- and long-term follow-up.

Decision tree–based machine learning analysis of intraoperative vasopressor use to optimize neurological improvement in acute spinal cord injury

OBJECTIVE

Previous work has shown that maintaining mean arterial pressures (MAPs) between 76 and 104 mm Hg intraoperatively is associated with improved neurological function at discharge in patients with acute spinal cord injury (SCI). However, whether temporary fluctuations in MAPs outside of this range can be tolerated without impairment of recovery is unknown. This retrospective study builds on previous work by implementing machine learning to derive clinically actionable thresholds for intraoperative MAP management guided by neurological outcomes.

METHODS

Seventy-four surgically treated patients were retrospectively analyzed as part of a longitudinal study assessing outcomes following SCI. Each patient underwent intraoperative hemodynamic monitoring with recordings at 5-minute intervals for a cumulative 28,594 minutes, resulting in 5718 unique data points for each parameter. The type of vasopressor used, dose, drug-related complications, average intraoperative MAP, and time spent in an extreme MAP range (< 76 mm Hg or > 104 mm Hg) were collected. Outcomes were evaluated by measuring the change in American Spinal Injury Association Impairment Scale (AIS) grade over the course of acute hospitalization. Features most predictive of an improvement in AIS grade were determined statistically by generating random forests with 10,000 iterations. Recursive partitioning was used to establish clinically intuitive thresholds for the top features.

RESULTS

At discharge, a significant improvement in AIS grade was noted by an average of 0.71 levels (p = 0.002). The hemodynamic parameters most important in predicting improvement were the amount of time intraoperative MAPs were in extreme ranges and the average intraoperative MAP. Patients with average intraoperative MAPs between 80 and 96 mm Hg throughout surgery had improved AIS grades at discharge. All patients with average intraoperative MAP > 96.3 mm Hg had no improvement. A threshold of 93 minutes spent in an extreme MAP range was identified after which the chance of neurological improvement significantly declined. Finally, the use of dopamine as compared to norepinephrine was associated with higher rates of significant cardiovascular complications (50% vs 25%, p < 0.001).

CONCLUSIONS

An average intraoperative MAP value between 80 and 96 mm Hg was associated with improved outcome, corroborating previous results and supporting the clinical verifiability of the model. Additionally, an accumulated time of 93 minutes or longer outside of the MAP range of 76–104 mm Hg is associated with worse neurological function at discharge among patients undergoing emergency surgical intervention for acute SCI.

Management of Thoracic Disc Pathology via the Lateral Approach: Advances Using the Minimally Invasive Approach and Navigation

Historically, thoracic disc pathology has been treated via open thoracotomy or open posterior costotransversectomy or lateral extracavitary approaches. However, these approaches are associated with approach-related morbidity. With advancement in such minimally invasive approaches as the lateral interbody fusion coupled with navigation, the morbidity of approaching anterior thoracic spinal pathology may be reduced. There are subtleties and nuances in the thoracic approaches that are different from the lateral lumbar interbody approaches. We discuss our technique of the minimally invasive approach to the thoracic spine, management of the rib and pleura, and incorporation of navigation into the procedure.

The Preoperative Cross-sectional Area of the Deep Cervical Extensor Muscles Does Not Predict Loss of Lordosis After Cervical Laminoplasty

STUDY DESIGN

This was a retrospective, single center.

OBJECTIVES

The objective of this study was to investigate the association between the cross-sectional area (CSA) of the deep extensor muscles (DEM) and postlaminoplasty alignment.

SUMMARY OF BACKGROUND DATA

The preoperative CSA of the semispinalis cervicis (SC) has been reported to correlate with loss of lordosis (LL) after laminoplasty, with a CSA <154.5 mm2 associated with a 10 degrees LL.

METHODS

Laminoplasty patients at the University of California San Francisco between 2009 and 2018 by 2 spine surgeons were retrospectively studied. Patients with previous cervical surgery or nondegenerative diagnoses were excluded. Measurements included the C2-C7 Cobb, T1 slope, and cervical sagittal vertical axis. Preoperative DEM CSA was measured on magnetic resonance imaging. Variables associated with lordosis were analyzed with univariate analysis and multivariate logistic regression, and association between postoperative cervical alignment and the musculature was evaluated.

RESULTS

Seventy-six patients with a mean age of 64 years were included. The average follow-up was 22.53 months. The overall average CSA of the DEM was 2274.55 mm2 and that of the SC was 275.64 mm2. Means of both CSAs were higher in men (P<0.001). Linear regression showed no correlation between LL with CSA of the DEM or the SC (r=0.005, P=0.119; r=0.001, P=0.095). Univariate and multivariate regression showed no differences in the CSA of the DEM and SC between groups with and without LL (P=0.092, 0.117 and 0.163, 0.292). There was no correlation in LL with sex or body mass index (P>0.05).

CONCLUSIONS

Preoperative CSA of the deep cervical extensor muscles may not predict LL after cervical laminoplasty. The correlation between the preoperative SC CSA and postoperative cervical alignment may not be as strong as previously reported.

Patient outcomes after circumferential minimally invasive surgery compared with those of open correction for adult spinal deformity: initial analysis of prospectively collected data

OBJECTIVE

Circumferential minimally invasive spine surgery (cMIS) for adult scoliosis has become more advanced and powerful, but direct comparison with traditional open correction using prospectively collected data is limited. The authors performed a retrospective review of prospectively collected, multicenter adult spinal deformity data. The authors directly compared cMIS for adult scoliosis with open correction in propensity-matched cohorts using health-related quality-of-life (HRQOL) measures and surgical parameters.

METHODS

Data from a prospective, multicenter adult spinal deformity database were retrospectively reviewed. Inclusion criteria were age > 18 years, minimum 1-year follow-up, and one of the following characteristics: pelvic tilt (PT) > 25°, pelvic incidence minus lumbar lordosis (PI-LL) > 10°, Cobb angle > 20°, or sagittal vertical axis (SVA) > 5 cm. Patients were categorized as undergoing cMIS (percutaneous screws with minimally invasive anterior interbody fusion) or open correction (traditional open deformity correction). Propensity matching was used to create two equal groups and to control for age, BMI, preoperative PI-LL, pelvic incidence (PI), T1 pelvic angle (T1PA), SVA, PT, and number of posterior levels fused.

RESULTS

A total of 154 patients (77 underwent open procedures and 77 underwent cMIS) were included after matching for age, BMI, PI-LL (mean 15° vs 17°, respectively), PI (54° vs 54°), T1PA (21° vs 22°), and mean number of levels fused (6.3 vs 6). Patients who underwent three-column osteotomy were excluded. Follow-up was 1 year for all patients. Postoperative Oswestry Disability Index (ODI) (p = 0.50), Scoliosis Research Society-total (p = 0.45), and EQ-5D (p = 0.33) scores were not different between cMIS and open patients. Maximum Cobb angles were similar for open and cMIS patients at baseline (25.9° vs 26.3°, p = 0.85) and at 1 year postoperation (15.0° vs 17.5°, p = 0.17). In total, 58.3% of open patients and 64.4% of cMIS patients (p = 0.31) reached the minimal clinically important difference (MCID) in ODI at 1 year. At 1 year, no differences were observed in terms of PI-LL (p = 0.71), SVA (p = 0.46), PT (p = 0.9), or Cobb angle (p = 0.20). Open patients had greater estimated blood loss compared with cMIS patients (1.36 L vs 0.524 L, p < 0.05) and fewer levels of interbody fusion (1.87 vs 3.46, p < 0.05), but shorter operative times (356 minutes vs 452 minutes, p = 0.003). Revision surgery rates between the two cohorts were similar (p = 0.97).

CONCLUSIONS

When cMIS was compared with open adult scoliosis correction with propensity matching, HRQOL improvement, spinopelvic parameters, revision surgery rates, and proportions of patients who reached MCID were similar between cohorts. However, well-selected cMIS patients had less blood loss, comparable results, and longer operative times in comparison with open patients.

Does reduction of the Meyerding grade correlate with outcomes in patients undergoing decompression and fusion for grade I degenerative lumbar spondylolisthesis?

OBJECTIVE

Reduction of Meyerding grade is often performed during fusion for spondylolisthesis. Although radiographic appearance may improve, correlation with patient-reported outcomes (PROs) is rarely reported. In this study, the authors' aim was to assess the impact of spondylolisthesis reduction on 24-month PRO measures after decompression and fusion surgery for Meyerding grade I degenerative lumbar spondylolisthesis.

METHODS

The Quality Outcomes Database (QOD) was queried for patients undergoing posterior lumbar fusion for spondylolisthesis with a minimum 24-month follow-up, and quantitative correlation between Meyerding slippage reduction and PROs was performed. Baseline and 24-month PROs, including the Oswestry Disability Index (ODI), EQ-5D, Numeric Rating Scale (NRS)-back pain (NRS-BP), NRS-leg pain (NRS-LP), and satisfaction (North American Spine Society patient satisfaction questionnaire) scores were noted. Multivariable regression models were fitted for 24-month PROs and complications after adjusting for an array of preoperative and surgical variables. Data were analyzed for magnitude of slippage reduction and correlated with PROs. Patients were divided into two groups: < 3 mm reduction and ≥ 3 mm reduction.

RESULTS

Of 608 patients from 12 participating sites, 206 patients with complete data were identified in the QOD and included in this study. Baseline patient demographics, comorbidities, and clinical characteristics were similarly distributed between the cohorts except for depression, listhesis magnitude, and the proportion with dynamic listhesis (which were accounted for in the multivariable analysis). One hundred four (50.5%) patients underwent lumbar decompression and fusion with slippage reduction ≥ 3 mm (mean 5.19, range 3 to 11), and 102 (49.5%) patients underwent lumbar decompression and fusion with slippage reduction < 3 mm (mean 0.41, range 2 to -2). Patients in both groups (slippage reduction ≥ 3 mm, and slippage reduction < 3 mm) reported significant improvement in all primary patient reported outcomes (all p < 0.001). There was no significant difference with regard to the PROs between patients with or without intraoperative reduction of listhesis on univariate and multivariable analyses (ODI, EQ-5D, NRS-BP, NRS-LP, or satisfaction). There was no significant difference in complications between cohorts.

CONCLUSIONS

Significant improvement was found in terms of all PROs in patients undergoing decompression and fusion for lumbar spondylolisthesis. There was no correlation with clinical outcomes and magnitude of Meyerding slippage reduction.

Utility of the MISDEF2 Algorithm and Extent of Fusion in Open Adult Spinal Deformity Surgery With Minimum 2-Year Follow-up

Objective

Long-segment fusion in adult spinal deformity (ASD) is often needed, but more focal surgeries may provide significant relief with less morbidity. The minimally invasive spinal deformity surgery (MISDEF2) algorithm guides minimally invasive ASD surgery, but it may be useful in open ASD surgery. We classified ASD patients undergoing focal decompression, limited decompression and fusion, and full correction according to MISDEF2 and correlated outcomes.

Methods

A retrospective study of ASD patients treated by 2 surgeons at our hospital was performed. Inclusion criteria were: age > 50, minimum 2-year follow-up, and open ASD surgery. Tumor, trauma, and infections were excluded. Patients had open surgery including focal decompression, short segment fusion, or full scoliosis correction. All patients were categorized by MISDEF2 into 4 classes based upon spinopelvic parameters. Perioperative metrics were assessed. Radiographic correction, complications and reoperation were recorded.

Results

A total of 136 patients met inclusion criteria. Mean follow-up was 46±15.8 months (range, 24–118 months). Forty-seven underwent full deformity correction, 71 underwent short segment fusion, and 18 underwent decompression alone. There were 24 cases of class I, 66 cases of class II, 23 cases of class III, and 23 cases of class IV patients. Patients in class I and II had perioperative complication rates of 0% and 16.7% and revision rates of 8% and 21.2% when undergoing focal decompression or limited fusion. However, class II patients undergoing full correction had higher perioperative complications rate (p=0.03) and revision surgery rates (p=0.047). This difference was not seen in class III patients (p>0.05). All class IV patients underwent full correction, but they had higher perioperative complication rates (p<0.019), comparable revision surgery rates (p=0.27), and better radiographic realignment (p<0.001). In addition, full deformity correction was associated with longer length of stay, increased blood loss, and longer operative time (p<0.001).

Conclusion

The MISDEF2 algorithm may help guide ASD surgical decision making even in open surgery, with focal treatment used in class I and II patients as a viable alternative and full correction implemented in class IV patients because of severe malalignment. However, class II patients with ASD undergoing full deformity correction do have higher complication rates.

Use of an exoscope for enhanced visualization of a Schwab grade 5 osteotomy to correct kyphotic deformity

The development of the 3D exoscope has advanced intraoperative visualization by providing access to visual corridors that were previously difficult to obtain or maintain with traditional operating microscopes. Favorable ergonomics, maneuverability, and increased potential for instruction provide utility in a large range of procedures. Here, the authors demonstrate the exoscope system in a patient with progressive thoracolumbar junctional kyphosis with bony retropulsion of a T12–L1 fracture requiring a Schwab grade 5 osteotomy and fusion. The utilization of the exoscope provides visual access to the ventrolateral dura for the entire surgical team (surgeons, learners, and scrub nurse).

The video can be found here: https://stream.cadmore.media/r10.3171/2021.10.FOCVID21190

Awake spinal surgery: simplifying the learning curve with a patient selection algorithm

OBJECTIVE

There is a learning curve for surgeons performing "awake" spinal surgery. No comprehensive guidelines have been proposed for the selection of ideal candidates for awake spinal fusion or decompression. The authors sought to formulate an algorithm to aid in patient selection for surgeons who are in the startup phase of awake spinal surgery.

METHODS

The authors developed an algorithm for selecting patients appropriate for awake spinal fusion or decompression using spinal anesthesia supplemented with mild sedation and local analgesia. The anesthetic protocol that was used has previously been reported in the literature. This algorithm was formulated based on a multidisciplinary team meeting and used in the first 15 patients who underwent awake lumbar surgery at a single institution.

RESULTS

A total of 15 patients who underwent decompression or lumbar fusion using the awake protocol were reviewed. The mean patient age was 61 ± 12 years, with a median BMI of 25.3 (IQR 2.7) and a mean Charlson Comorbidity Index of 2.1 ± 1.7; 7 patients (47%) were female. Key patient inclusion criteria were no history of anxiety, 1 to 2 levels of lumbar pathology, moderate stenosis and/or grade I spondylolisthesis, and no prior lumbar surgery at the level where the needle is introduced for anesthesia. Key exclusion criteria included severe and critical central canal stenosis or patients who did not meet the inclusion criteria. Using the novel algorithm, 14 patients (93%) successfully underwent awake spinal surgery without conversion to general anesthesia. One patient (7%) was converted to general anesthesia due to insufficient analgesia from spinal anesthesia. Overall, 93% (n = 14) of the patients were assessed as American Society of Anesthesiologists class II, with 1 patient (7%) as class III. The mean operative time was 115 minutes (± 60 minutes) with a mean estimated blood loss of 46 ± 39 mL. The median hospital length of stay was 1.3 days (IQR 0.1 days). No patients developed postoperative complications and only 1 patient (7%) required reoperation. The mean Oswestry Disability Index score decreased following operative intervention by 5.1 ± 10.8.

CONCLUSIONS

The authors propose an easy-to-use patient selection algorithm with the aim of assisting surgeons with patient selection for awake spinal surgery while considering BMI, patient anxiety, levels of surgery, and the extent of stenosis. The algorithm is specifically intended to assist surgeons who are in the learning curve of their first awake spinal surgery cases.

Classifying Patients Operated for Spondylolisthesis: A K-Means Clustering Analysis of Clinical Presentation Phenotypes

BACKGROUND

Trials of lumbar spondylolisthesis are difficult to compare because of the heterogeneity in the populations studied.

OBJECTIVE

To define patterns of clinical presentation.

METHODS

This is a study of the prospective Quality Outcomes Database spondylolisthesis registry, including patients who underwent single-segment surgery for grade 1 degenerative lumbar spondylolisthesis. Twenty-four-month patient-reported outcomes (PROs) were collected. A k-means clustering analysis-an unsupervised machine learning algorithm-was used to identify clinical presentation phenotypes.

RESULTS

Overall, 608 patients were identified, of which 507 (83.4%) had 24-mo follow-up. Clustering revealed 2 distinct cohorts. Cluster 1 (high disease burden) was younger, had higher body mass index (BMI) and American Society of Anesthesiologist (ASA) grades, and globally worse baseline PROs. Cluster 2 (intermediate disease burden) was older and had lower BMI and ASA grades, and intermediate baseline PROs. Baseline radiographic parameters were similar (P > .05). Both clusters improved clinically (P < .001 all 24-mo PROs). In multivariable adjusted analyses, mean 24-mo Oswestry Disability Index (ODI), Numeric Rating Scale Back Pain (NRS-BP), Numeric Rating Scale Leg Pain, and EuroQol-5D (EQ-5D) were markedly worse for the high-disease-burden cluster (adjusted-P < .001). However, the high-disease-burden cluster demonstrated greater 24-mo improvements for ODI, NRS-BP, and EQ-5D (adjusted-P < .05) and a higher proportion reaching ODI minimal clinically important difference (MCID) (adjusted-P = .001). High-disease-burden cluster had lower satisfaction (adjusted-P = .02).

CONCLUSION

We define 2 distinct phenotypes-those with high vs intermediate disease burden-operated for lumbar spondylolisthesis. Those with high disease burden were less satisfied, had a lower quality of life, and more disability, more back pain, and more leg pain than those with intermediate disease burden, but had greater magnitudes of improvement in disability, back pain, quality of life, and more often reached ODI MCID.