Global Spine Journal

Retrospective cohort study.

To determine the effect of obesity (body mass index >30 kg/m²) on perioperative morbidity and mortality after surgical decompression of spinal metastases.

The American College of Surgeons National Surgical Quality Improvement Program database is a large multicenter clinical registry that collects preoperative risk factors, intraoperative variables, and 30-day postoperative morbidity and mortality outcomes from hospitals nationwide. Current Procedural Terminology codes were used to query the database for adults who underwent decompression with laminectomy for treatment of metastatic spinal lesions between 2010 and 2014. Patients were separated into 2 cohorts based on the presence of absence of obesity. Univariate analysis and multivariate logistic regression analysis were used to analyze the effect of obesity on perioperative morbidity and mortality.

There was a significantly higher rate of venous thromboembolism (VTE; obese 6.6% vs nonobese 4.2%; P = .01) and pulmonary complications (obese 2.6% vs nonobese 2.2%; P = .046) in the obese group compared with the nonobese group. The nonobese group had prolonged hospitalization (obese 62.0% vs nonobese 69.0%; P = .001) and a higher incidence of blood transfusions (obese 26.8% vs nonobese 34.2%; P < .001). On multivariate analysis, obesity was found to be an independent risk factor for VTE (odds ratio = 1.75, confidence interval = 1.17-2.63, P = .007).

Obese patients were predisposed to an elevated risk of VTE following laminectomy for spinal metastases. Early postoperative mobilization and a low threshold to evaluate for perioperative VTE are important in these patients in order to appropriately diagnose and treat these complications and minimize morbidity.

Retrospective cohort.

To analyze the outcome of surgical correction of children with caudal regression syndrome.

The study included 12 patients aged 1.5 to 9 years with caudal regression syndrome. In order determine the type of caudal regression, the Renshaw Classification was used. The surgery included correction and stabilization of the kyphotic deformity at the unstable lumbosacral region, with reconstruction of the sagittal balance using a bony block constructed from allograft. Short- and long-term outcomes were evaluated. The study was approved by the local institutional review board.

Children with types III and IV caudal regression syndrome underwent spinal-pelvic fusion, with 100% fusion rate, which allows sufficient stabilization of the lumbopelvic segment permitting patient mobilization and standing in type III patients. There were 5 complications needing additional care.

Multilevel pedicular screw fixation in combination with spinopelvic fusion with cortical allografts allows reconstruction of the sagittal alignment with solid bony fusion improving the quality of life for these patients.

Retrospective cohort study.

To compare postoperative changes of cervical sagittal alignment (CSA) and cervical sagittal balance (CSB) after laminoplasty between cervical spondylotic myelopathy (CSM) and ossification of the posterior longitudinal ligament (OPLL) and to examine impacts of these radiologic changes on neurologic outcomes.

A total of 168 consecutive patients with CSM (CSM group) and 51 consecutive patients with OPLL (OPLL group) were included. As indicators of CSA and CSB, the C2-7 angle and C1-C7 sagittal vertical axis (SVA) were, respectively, measured before surgery and at 2-year follow-up. Neurologic status was assessed using the Japanese Orthopaedic Association score before surgery and at 2-year follow-up.

Whereas both postoperative loss of C2-7 angle and increase of C1-C7 SVA were significantly greater in the elderly subgroup of the CSM group, patient age did not significantly affect these changes in the OPLL group. Preservation of C7 maintained C1-C7 SVA at postoperative 2 years only in the CSM group. Postoperative cervical kyphosis and sagittal imbalance significantly decreased neurologic improvement in the CSM group but not in the OPLL group.

Elderly patients with CSM have significantly greater postoperative loss of lordosis and increase in C1-C7 SVA than nonelderly patients, and both postoperative kyphotic deformity and sagittal imbalance significantly deteriorate neurologic recovery. On the other hand, although patients with OPLL, irrespective of patient age and preservation of C7, have significantly more loss of lordosis and increase in C1-C7 SVA than CSM patients, neither postoperative kyphotic deformity nor sagittal imbalance significantly deteriorates neurologic recovery in OPLL patients.

A nonrandomized, two-armed prospective study.

Water-tight dural closure is paramount to the prevention of cerebrospinal fluid (CSF) leakage and associated complications. Synthetic polyethylene glycol (PEG) hydrogel has been used as an adjunct to sutured dural repair; however, its expansion postoperatively is a concern for neurological complications. A low-swell formulation of PEG sealant was introduced as DuraSeal Exact Spine Sealant System (DESS). A Post-Approval Study was performed primarily to evaluate the safety and efficacy of DESS for spinal dural repair compared to current alternatives, in a large patient population, reflecting a real-world practice.

A total of 36 sites in the United States enrolled 429 patients treated with DESS as an adjunct to dural repair in the spinal sealant group and 406 patients treated with all other modalities in the control arm, from October 2011 to June 2016. The primary endpoint was the incidence of CSF leak within 90 days of operation. The secondary endpoints evaluated were deep surgical site infection and neurological serious adverse events.

The CSF leakage in the DESS group (6.6%) was not significantly different from the control group (6.5%) (p = .83), and there was no significant difference in the time to first leak. The two groups had no significant differences in deep surgical site infection (1.6% versus control 2.1%, p = .61) or proportion of subjects with neurological serious adverse events (2.9% versus control 1.6%, p = .516).

DuraSeal Exact Spinal Sealant is safe when compared to current alternatives for spinal dural repair.

Retrospective study. Level of evidence III.

Postoperative complications in spine surgery are associated with increased morbidity, hospital length of stay, and health care costs. Registry of complications in orthopedics and the spine surgery is heterogeneous.

Between July 2016 and June 2017, 274 spinal surgeries were performed, the presence of postoperative complications was analyzed at 90 days (according to the classification of Dindo-Clavien, grades I-V), hospital length of stay, surgical complexity (low, medium, and high), unplanned readmission, and risk factors were evaluated.

A total of 79 patients suffered a complication (28.8%), of them 21 (26.7%) were grade I, 24 (30.3%) were grade II, 4 (5.7%) were grade IIIA, and 29 (37.3%) were grade IIIB. There were no IV and V grade cases. The most frequent complication was excessive pain followed by deep wound infection and anemia. Surgical complexity and surgical time were significantly associated with the risk of developing a complication. The average number of hospital length of stay in patients without and with complications were 2.7 and 10.6, respectively, and the unplanned readmission rate was 11%.

Registry of postoperative complications allows the correct standardization and risk factors required to establish measures to decrease them, the application of Dindo-Clavien classification was useful for the purpose of our study.

Retrospective database study.

To investigate the impact obstructive sleep apnea (OSA) has on perioperative complications, inpatient mortality, and costs in patients undergoing spinal fusions.

Hospitalizations for spinal fusion surgery between the years 2009 and 2011 were identified using the Nationwide Inpatient Sample and grouped into patients with and without OSA. Patient demographic data, comorbidities, hospital characteristics, hospitalization outcomes, and costs were extracted and compared. Multivariable logistic regressions were conducted to compare the in-hospital outcomes of patients undergoing spinal fusion with and without OSA.

A total of 107 451 (7.7%) OSA patients who underwent spinal fusions were identified from 2009 to 2011. Compared with patients without OSA, OSA patients were significantly older, more likely to be male, and have significantly greater comorbidity burden. Multivariable regression analysis demonstrated that OSA had a significant independent association with slightly increased respiratory (odds ratio [OR] = 1.13, confidence interval [CI] = 1.09-1.16; P < .001), urinary and renal (OR = 1.11, CI = 1.07-1.16; P < .001) or overall inpatient complications (OR = 1.05, CI = 1.02-1.05; P < .001). OSA was also independently associated with significantly lower inpatient mortality (OR = 0.39, CI = 0.33-0.45; P < .001).

While OSA confers greater comorbidity burden and is associated with slightly higher inpatient complication rates following spinal fusions, diagnosed OSA was not an independent predictor of inpatient mortality. A cautious interpretation of this finding is that on a national level, the current methods of preoperative medical optimization and inpatient management of OSA are satisfactory.

A retrospective cohort study.

To investigate factors influencing the incidence of moderate to severe postoperative axial neck pain following cervical laminoplasty.

We reviewed 125 patients with cervical myelopathy who underwent double-door laminoplasty. The primary outcomes were the Numerical Rating Scale score (NRS score, 0-10) for neck pain, the Short Form 36 (SF-36) Health Survey score (Physical and Mental Component Summary scores [PCS and MCS, respectively]), and satisfaction. Imaging parameters on plain radiographs and magnetic resonance imaging were also evaluated. Patients with moderate to severe postoperative neck pain (NRS ≥ 5) were compared with those with no or mild neck pain (NRS ≤ 4).

One hundred and three patients (82%) with complete data were eligible for inclusion. There were 67 men and 36 women, with a mean age of 65 years (32-89 years). Twenty-five patients (23%) had moderate to severe postoperative axial pain (NRS ≥ 5) and were compared with the other 78 patients (NRS ≤ 4), which revealed several predictive factors, including female sex, the presence of preoperative neck pain, low postoperative PCS, low preoperative and postoperative MCS, and satisfaction with the treatment. Multivariable logistic regression analysis revealed that the postoperative MCS (P = .002) was a risk factor for postoperative neck pain, although the preoperative MCS did not reach statistical significance (P = .06).

Patients with a low mental state, possibly before surgery, are at a high risk for postoperative axial neck pain. None of the imaging parameters were statistically different.

Retrospective cohort.

To study evidence to assess the impact of chronic obstructive pulmonary disease (COPD) on 30-day outcomes following 1- to 2-level anterior cervical discectomy and fusion (ACDF).

The 2015-2016 American College of Surgeons-National Surgical Quality Improvement Program (ACS-NSQIP) database was queried using Current Procedural Terminology (CPT) codes 22 551 (single-level) and 22 552 (additional level). Patients undergoing disc arthroplasty, multilevel (>2) fusion, posterior cervical spine surgery, and patients with fracture, tumor, and/or infection were excluded.

Out of 14 835 patients undergoing an elective 1- to 2-level ACDF, 649 (4.4%) had a diagnosis of COPD at the time of the surgery. Following adjusted logistic regression analysis, prior history of COPD was significantly associated with a longer length of stay (odds ratio [OR] 1.25 [95% confidence interval (CI0 1.04-1.52]; P = .019), superficial surgical site infection (OR 2.68 [95% CI 1.06-6.80]; P = .038), discharge destination other than home (OR 1.49 [95% CI 1.05-2.12]; P = .026), pneumonia (OR 4.37 [95% CI 2.42-7.88]; P < .001), ventilator use >48 hours (OR 5.34 [95% CI 1.88-15.15]; P = .002), unplanned reintubation (OR 3.36 [1.48-7.62]; P = .004), and 30-day readmissions (OR 1.69 [95% CI 1.20-2.38]; P = .003).

The findings of this study show that COPD patients are more likely to have postoperative complications and 30-day readmissions, despite elective ACDF itself being a low-risk surgery in general. Results show that majority of the complications were pulmonary in nature, further stressing the need for accurate medical optimization following surgery in these patients.

Retrospective cohort study.

Factors that predict outcomes for adult cervical spine deformity (ACSD) have not been well defined. To compare ACSD patients with best versus worst outcomes.

This study was based on a prospective, multicenter observational ACSD cohort. Best versus worst outcomes were compared based on Neck Disability Index (NDI), Neck Pain Numeric Rating Scale (NP-NRS), and modified Japanese Orthopaedic Association (mJOA) scores.

Of 111 patients, 80 (72%) had minimum 1-year follow-up. For NDI, compared with best outcome patients (n = 28), worst outcome patients (n = 32) were more likely to have had a major complication (P = .004) and to have undergone a posterior-only procedure (P = .039), had greater Charlson Comorbidity Index (P = .009), and had worse postoperative C7-S1 sagittal vertical axis (SVA; P = .027). For NP-NRS, compared with best outcome patients (n = 26), worst outcome patients (n = 18) were younger (P = .045), had worse baseline NP-NRS (P = .034), and were more likely to have had a minor complication (P = .030). For the mJOA, compared with best outcome patients (n = 16), worst outcome patients (n = 18) were more likely to have had a major complication (P = .007) and to have a better baseline mJOA (P = .030). Multivariate models for NDI included posterior-only surgery (P = .006), major complication (P = .002), and postoperative C7-S1 SVA (P = .012); models for NP-NRS included baseline NP-NRS (P = .009), age (P = .017), and posterior-only surgery (P = .038); and models for mJOA included major complication (P = .008).

Factors distinguishing best and worst ACSD surgery outcomes included patient, surgical, and radiographic factors. These findings suggest areas that may warrant greater awareness to optimize patient counseling and outcomes.

A retrospective cohort study.

The objective of this study was to identify important predictors of poor functional recovery in patients undergoing surgery for cervical ossification of the posterior longitudinal ligament (OPLL).

This was a retrospective cohort study of 142 OPLL patients with laminoplasty; 135 had complete radiographical data and were followed up for ≥2 years. The following OPLL characteristics were compared between patients with “good” and “poor” outcomes (Japanese Orthopedic Association [JOA] recovery rate ≥50% and <50%, respectively): number of ossified levels, OPLL classification, ossification shape, K-line, canal-occupying ratio, and increased magnetic resonance imaging (MRI) signal intensity. Predictors of functional recovery were identified.

Pre- and postoperative (2 years following surgery) JOA scores were 10.6 ± 2.9 and 14.1 ± 2.2, respectively, indicating significant improvement following laminoplasty (P < .001). The average JOA recovery rate was 53.4% ± 34.7%, with 81 (60.0%) and 54 (40.0%) patients in the better and poorer neurological outcome groups, respectively. The canal occupation ratio of OPLL ≤60%/>60% were 117 (86.7%) and 18 (13.3%) patients, respectively. In the stepwise logistic regression analysis, an occupation ratio greater than 60% was identified as a significant factor for poor postoperative neurological outcome (relative risk, 4.82; 95% confidential interval, 1.61-14.46, P = .005).

This multivariate analysis demonstrated a large size OPLL (occupying ratio >60%) was associated with a risk of poor neurological recovery roughly 5 times greater, and therefore other types of surgery are recommended in cases with such a ratio.

Retrospective cohort study.

Malnutrition has been shown to be a risk factor for poor perioperative outcomes in multiple surgical subspecialties, but few studies have specifically investigated the effect of hypoalbuminemia in patients undergoing operative treatment of metastatic spinal tumors. The aim of this study was to assess the role of hypoalbuminemia as an independent risk factor for 30-day perioperative mortality and morbidity after surgical decompression of metastatic spinal tumors using the American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) database from 2011 to 2014.

We identified 1498 adult patients in the ACS-NSQIP database who underwent laminectomy and excision of metastatic extradural spinal tumors. Patients were categorized into normoalbuminemic and hypoalbuminemic (ie, albumin level <3.5 g/dL) groups. Univariate and multivariate regression analyses were performed to examine the association between preoperative hypoalbuminemia and 30-day perioperative mortality and morbidity. Subgroup analysis was performed in the hypoalbuminemic group to assess the dose-dependent effect of albumin depletion.

Hypoalbuminemia was associated with increased risk of perioperative mortality, any complication, sepsis, intra- or postoperative transfusion, prolonged hospitalization, and non-home discharge. However, albumin depletion was also associated with decreased risk of readmission. There was an albumin level–dependent effect of increasing mortality and complication rates with worsening albumin depletion.

Hypoalbuminemia is an independent risk factor for perioperative mortality and morbidity following surgical decompression of metastatic spinal tumors with a dose-dependent effect on mortality and complication rates. Therefore, it is important to address malnutrition and optimize nutritional status prior to surgery.

Narrative review.

To discuss the relationship between degenerative cervical myelopathy (DCM) and vitamin B₁₂ deficiency. Specifically, it is the aim to outline the rational for future research into assessment and therapeutic optimization of vitamin B₁₂ in the treatment of DCM.

Literature review.

DCM is the commonest cause of spinal cord impairment, with an average age of presentation in the sixth decade. Patients at this age have also been reported to have a high prevalence of vitamin B₁₂ deficiency, with estimates of up to 20% in the elderly. Vitamin B₁₂ deficiency can result in subacute combined degeneration of the spinal cord (SACD), and several case reports have pointed to patients with both DCM and SACD. Both SACD and reversible compressive injury due to DCM necessitate remyelination in the spinal cord, a process that requires adequate vitamin B₁₂ levels. Basic science research on nerve crush injuries have shown that vitamin B₁₂ levels are altered after nerve injury and that vitamin B₁₂ along with dexamethasone or nonsteroidal anti-inflammatory drugs can reduce Wallerian degeneration. Furthermore, it has been suggested that a combination of B-vitamins can reduce glutamate-induced neurotoxicity.

Given the high prevalence of clinical and subclinical vitamin B₁₂ deficiency in the elderly, the role of vitamin B₁₂ in myelination, and vitamin B₁₂ deficiency as a differential diagnosis of DCM, it is important to investigate what role vitamin B₁₂ levels play in patients with DCM in terms of baseline neurological function and whether optimization of vitamin B₁₂ levels can improve surgical outcome. Furthermore, the routine assessment of vitamin B₁₂ levels in patients considered for DCM surgery should be considered.

Systematic literature review.

Many studies have provided evidence that short-segment posterior fixation (SSPF—1 level above and 1 below) with screws at the fracture level (SFL) are enough to achieve stability in some injury patterns, such as burst fractures, avoiding the need for circumferential reconstruction and long-segment instrumented fusion (LSIF—at least 2 levels above and 2 below). Given the potential benefits of avoiding unnecessary fusion in mobile healthy spinal segments, we performed a systematic review of biomechanical studies comparing different spinal reconstruction techniques for fractures of the thoracolumbar spine.

A systematic literature review was performed in the PubMed and OVID databases of biomechanical studies comparing biomechanical differences between techniques of spine reconstructions.

Eight studies were included and evaluated. Five of 6 studies reported stiffness improvement with SSPF and SFL, even comparable to circumferential fusion for a burst fracture. Two studies reported that LSPF has higher stiffness and restricts range of motion better than SSPF, but inclusion of screws in the fracture level is similar to LSPF (1 study). Finally, although SSPF is less stiff than anterior reconstruction, adding a SFL in SSPF results in similar stiffness than circumferential fusion for unstable burst fractures.

Biomechanical studies analyzed generally suggested that SFL in SSPF may improve construction stiffness, and can even be compared with long-segment fixation or circumferential reconstruction in some scenarios. This construct option may be used to enhance stiffness in selected injury patterns, avoiding the needs of an additional anterior approach.

Systematic review.

To assess the efficacy of kyphoplasty in controlling pain and improving quality of life in oncologic patients with metastatic spinal disease and pathologic compression fractures of the spine.

A literature search through medical database was conducted (using PubMed, EMBASE, Cochrane, and LILACS) for randomized controlled trials comparing balloon kyphoplasty versus the traditional treatment for compression fractures of the spine due to metastatic disease. Two investigators independently assessed all titles and abstracts to select potential articles to be included. Inclusion criteria consisted of randomized controlled trials involving patients with pathologic compression fractures due to spinal metastasis or multiple myeloma treated with balloon kyphoplasty procedure as one of the study interventions, while the control group was any other treatment modality. The risk of bias in individual studies was assessed.

Two studies, with a combined total of 181 patients, met inclusion criteria. Because of data heterogeneity, the meta-analysis was not possible, and individual analysis of studies was performed. There is moderate evidence that patients treated with balloon kyphoplasty displayed better scores for pain (Numeric Rating Scale), disability (Roland-Morris Disability Questionnaire), quality of life (Short Form–36 Health Survey), and functional status (Karnofsky Performance Status) compared with those undergoing the conventional treatment. Patients treated with kyphoplasty also have better recovery of vertebral height.

This study concluded that balloon kyphoplasty could be considered as an early treatment option for patients with symptomatic neoplastic spinal disease, although further randomized clinical trials should be performed for improvement of the quality of evidence.