A Review of Vitamin D in Spinal Surgery: Deficiency Screening, Treatment, and Outcomes

In this review, we discuss the demonstrated value of vitamin D in bone maintenance, fracture resistance, spinal health, and spine surgery outcomes. Despite this, the effect of vitamin D levels in spine surgery has not been well described. Through this review of literature, several conclusions were drawn. First, despite the fact that a high number of spine surgery patients are vitamin D deficient, screening is not commonly performed. Second, adequate vitamin D levels will not be achieved in a majority of these patients without supplementation. Last, inadequate vitamin D levels may increase the risk of pseudarthrosis. Given these findings, we suggest that many patients undergoing spinal surgery could be treated with vitamin D supplementation prior to surgery without the need for confirmatory testing for vitamin D deficiency. This is a more cost-effective method than screening all patients. However, future randomized trials and cost-effectiveness analyses are needed to determine the ultimate effects of vitamin D supplementation on clinical morbidity and surgical outcomes.

Etiology-Based Classification of Adjacent Segment Disease Following Lumbar Spine Fusion

BACKGROUND

Adjacent segment disease (ASDz) is a potential complication following lumbar spinal fusion. A common nomenclature based on etiology and ASDz type does not exist and is needed to assist with clinical prognostication, decision making, and management.

QUESTIONS/PURPOSES

The objective of this study was to develop an etiology-based classification system for ASDz following lumbar fusion.

METHODS

We conducted a retrospective chart review of 65 consecutive patients who had undergone both a lumbar fusion performed by a single surgeon and a subsequent procedure for ASDz. We established an etiology-based classification system for lumbar ASDz with the following six categories: "degenerative" (degenerative disc disease or spondylosis), "neurologic" (disc herniation, stenosis), "instability" (spondylolisthesis, rotatory subluxation), "deformity" (scoliosis, kyphosis), "complex" (fracture, infection), or "combined." Based on this scheme, we determined the rate of ASDz in each etiologic category.

RESULTS

Of the 65 patients, 27 (41.5%) underwent surgery for neurogenic claudication or radiculopathy for adjacent-level stenosis or disc herniation and were classified as "neurologic." Ten patients (15.4%) had progressive degenerative disc pathology at the adjacent level and were classified as "degenerative." Ten patients (15.4%) had spondylolisthesis or instability and were classified as "instability," and three patients (4.6%) required revision surgery for adjacent-level kyphosis or scoliosis and were classified as "deformity." Fifteen patients (23.1%) had multiple diagnoses that included a combination of categories and were classified as "combined."

CONCLUSION

This is the first study to propose an etiology-based classification scheme of ASDz following lumbar spine fusion. This simple classification system may allow for the grouping and standardization of patients with similar pathologies and thus for more specific pre-operative diagnoses, personalized treatments, and improved outcome analyses.

Stability-preserving decompression in degenerative versus congenital spinal stenosis: demographic patterns and patient outcomes

BACKGROUND CONTEXT

Although lumbar spinal stenosis often presents as a degenerative condition (degenerative stenosis [DS]), some patients present with symptoms from lifelong narrowing of the spinal canal. These patients have congenital stenosis (CS) and present with symptoms of stenosis at a younger age. Patients with CS often have a distinct pathophysiology with fewer degenerative changes but present with multilevel involvement. In the setting of neurologic symptoms, decompression alone while preserving stability has been proposed for both patient populations.

PURPOSE

The purpose of this study is to evaluate if the different etiology for narrowing in CS and DS results in a different natural history of pain progression, different locations requiring decompression, and different outcomes following a stability-preserving decompression procedure.

STUDY DESIGN/SETTING

This study used a retrospective cohort study patient sample: We retrospectively reviewed consecutive patients of a single surgeon with DS or CS who underwent surgical decompression without fusion between 2008 and 2014. Patients were excluded if they had undergone a previous lumbar surgical procedure (decompression or fusion) or follow-up less than 12 months.

OUTCOME MEASURES

Pre- and postoperative clinical outcome scores including visual analogue scale (VAS) and Oswestry Disability Index (ODI) were recorded. Postoperatively, data were collected regarding complications, the presence of new radicular or myelopathic symptoms, and necessity of reoperation in the lumbar spine.

METHODS

Demographic information included age, sex, body mass index, smoking status, and Charleston Comorbidity Index (CCI). Preoperative clinical symptoms as well as the presence of lower extremity radiculopathy and claudication were evaluated. Patients were determined to have a diagnosis of CS by the treating surgeon if primary radiographs revealed shortened pedicles and decreased cross-sectional area of the spinal canal as detailed by previous studies. Binary outcomes were compared between congenital and degenerative cohorts using bivariate and multivariate logistic regression. Multivariate regressions controlled for baseline patient and operative characteristics.

RESULTS

The average age of the DS cohort was 66.7±10.7 years, whereas for the CS group, it was 47.1±9.2 years. Average follow-up was 27.6 months. The patients with DS had significantly more comorbidities as shown by the CCI score (2.8±1.6 vs. 0.5±0.6); p<.001) and the American Society of Anesthesiologists (ASA) score ≥3 (52.8% vs. 11.1%; p<.001). Patients with CS presented with higher VAS back (8.0 vs. 5.1; p=.008) and leg (7.9 vs. 4.5; p<.001) scores. Patients with DS presented with significantly greater duration of preoperative back pain and leg pain (42.7 vs. 30.5 months; p=.042). Postoperatively, there were no significant differences in VAS back, leg, or ODI scores. However, a trend toward a lower VAS leg score was present in the patients with CS when compared with patients with DS (2.6±3.0 vs. 4.2±3.2; p<.117). Both patient groups experienced similar levels of symptomatic relief and improvement in VAS and ODI scores. There were no significant differences in new-onset radicular symptoms requiring conservative treatment or reoperation. In both groups combined, 81.9% of patients reported resolution of lower extremity symptoms at final follow-up. Overall, 20.6% of patients experienced new lower-extremity radicular symptoms after a period of resolution of symptoms postoperatively. There were significantly more reoperations following surgical decompression in patients with DS (13.9% vs. 2.8%; p=.02).

CONCLUSIONS

Patients with CS and patients with DS respond well to decompression alone, without a supplemental fusion, despite differences in pain experience and presentation. The localization of pathology requiring decompression is similar. The patients with DS were more susceptible to require another operation resulting in a fusion, which confirms the theory that initial microinstability can progress in DS, but is likely not part of the disease process in CS. At just over 2 years after decompression, patients with CS may not need to be treated by a fusion in the setting of lower back pain; however, longer-term follow up is necessary to further assess these outcomes.

Preoperative mental health status may not be predictive of improvements in patient-reported outcomes following an anterior cervical discectomy and fusion

OBJECTIVE

Prior studies have correlated preoperative depression and poor mental health status with inferior patient-reported outcomes following lumbar spinal procedures. However, literature regarding the effect of mental health on outcomes following cervical spinal surgery is limited. As such, the purpose of this study is to test for the association of preoperative SF-12 Mental Component Summary (MCS) scores with improvements in Neck Disability Index (NDI), SF-12 Physical Component Summary (PCS), and neck and arm pain following anterior cervical discectomy and fusion (ACDF).

METHODS

A prospectively maintained surgical database of patients who underwent a primary 1- or 2-level ACDF during 2014–2015 was reviewed. Patients were excluded if they did not have complete patient-reported outcome data for the preoperative or 6-week, 12-week, or 6-month postoperative visits. At baseline, preoperative SF-12 MCS score was assessed for association with preoperative NDI, neck visual analog scale (VAS) score, arm VAS score, and SF-12 PCS score. The preoperative MCS score was then tested for association with changes in NDI, neck VAS, arm VAS, and SF-12 PCS scores from the preoperative visit to postoperative visits. These tests were conducted using multivariate regression controlling for baseline characteristics as well as for the preoperative score for the patient-reported outcome being assessed.

RESULTS

A total of 52 patients were included in the analysis. At baseline, a higher preoperative MCS score was negatively associated with a lower preoperative NDI (coefficient: −0.74, p < 0.001) and preoperative arm VAS score (−0.06, p = 0.026), but not preoperative neck VAS score (−0.03, p = 0.325) or SF-12 PCS score (0.04, p = 0.664). Additionally, there was no association between preoperative MCS score and improvement in NDI, neck VAS, arm VAS, or SF-12 PCS score at any of the postoperative time points (6 weeks, 12 weeks, and 6 months, p > 0.05 for each). The percentage of patients achieving a minimum clinically important difference at 6 months did not differ between the bottom and top MCS score halves (p > 0.05 for each).

CONCLUSIONS

The results of this study suggest that better preoperative mental health status is associated with lower perceived preoperative disability but is not associated with severity of preoperative neck or arm pain. In contrast to other studies, the present study was unable to demonstrate that preoperative mental health is predictive of improvement in patient-reported outcomes at any postoperative time point following an ACDF.

Case of a Missed Giant Cell Tumor of Bone: An Opportunity to Observe its Natural History Disease

Giant cell tumor of bone (GCT) is a benign neoplasm that most commonly presents with pain and is rarely diagnosed as an incidental finding. We present the report of a young woman whose pre-operative MRI was only noted to have a tear of the anterior cruciate ligament (ACL). Subsequently, the patient underwent anACL reconstruction. A second MRI, performed four years later, demonstrated an enlarged mass in the same location. A retrospective evaluation of the initial MRI revealed an eccentric metaphyseal lesion. Histology obtained from the lesion demonstrated a giant cell tumor of bone. We present the case of an asymptomatic GCT discovered retrospectively as an incidental finding and reevaluated four years later. 'Ihis case serves as a reminder of the importance for the critical review of routine preoperative imaging and also offers a unique perspective on the natural history of giant cell tumor of bone.

Comparison of the lumbar disc herniation patients randomized in SPORT to 6,846 discectomy patients from NSQIP: demographics, perioperative variables, and complications correlate well

BACKGROUND CONTEXT

The Spine Patient Outcomes Research Trial (SPORT) is a highly referenced clinical trial that randomized patients with lumbar pathology to receive surgery or continued conservative treatment.

PURPOSE

The purpose of this study was to compare the SPORT lumbar disc herniation cohort and an analogous cohort from the National Surgical Quality Improvement Program (NSQIP) database.

STUDY DESIGN/SETTING

This is a retrospective cohort study comparing a national database population to a randomized clinical trial.

PATIENT SAMPLE

Elective lumbar discectomies from NSQIP between 2010 and 2012 were used.

OUTCOME MEASURES

Demographics were compared between the randomized SPORT cohorts (surgical and nonoperative) and NSQIP. Perioperative factors and complications were then compared between SPORT discectomy patients and NSQIP.

METHODS

Using current procedural terminology and International Classification of Diseases, ninth revision codes, all elective lumbar discectomies from NSQIP between 2010 and 2012 were identified. Where possible based on the published data and variables available in each cohort, the two populations were compared.

RESULTS

A total of 6,846 NSQIP discectomy patients were compared with the randomized SPORT surgical and nonoperative cohorts. Demographic comparisons showed that NSQIP patients were older (average age 48.2±14.5 years [mean±standard deviation] vs. 41.7±11.8 and 43.0±11.3 years, respectively [p<.001]) and had higher body mass index (29.6±6.2 kg/m(2) vs. 27.8±5.6 and 28.2±5.4 kg/m(2), respectively [p<.001]). No statistical differences existed for gender or race. Smoking status was not different between the SPORT nonoperative group and NSQIP but was higher in NSQIP compared with SPORT surgical patients (p=.020 by 7%). Comparisons of perioperative factors and complications between the SPORT surgical cohort and NSQIP showed no statistical difference in average operative time, length of stay, deep wound infections, wound dehiscence, total wound complications, or blood transfusions. Spine Patient Outcomes Research Trial superficial wound infection rates were higher than NSQIP (p=.029 by 1.4%). As expected, SPORT 1-year reoperation rates were higher than NSQIP 30-day rates (7% vs. 2%, p<.001).

CONCLUSIONS

Spine Patient Outcomes Research Trial lumbar disc herniation results are similar to those from a large national patient sample. Even statistically significant differences would be considered clinically similar. These findings support the generalizability of the SPORT lumbar disc herniation results.

The surgical treatment of single level multi-focal subarticular and paracentral and/or far-lateral lumbar disc herniations: the single incision full endoscopic approach

BACKGROUND

Surgery for same level multi-focal extruded lumbar disc herniations is technically challenging and the optimal method controversial. The subarticular disc herniation may pose the most challenging subtype requiring partial or complete facetectomy with or without fusion. The far-lateral disc herniation, often treated using a Wiltse approach, can also be difficult to access especially in the obese patient. When both the subarticular and far-lateral subtypes are simultaneously present at the same level with or without a paracentral disc herniation, a total facetectomy and interbody fusion (TLIF) or a total disc replacement (TDR) may be necessary. Endoscopic surgical techniques may reduce the need for these more invasive methods.

METHODS

Fifteen patients (6 male and 9 female) who had same level multi-focal (subarticular as well as far-lateral and/or paracentral) extruded disc herniations underwent single incision unilateral endoscopic disc excision by the same surgeon at a single institution. Patients were prospectively followed for an average of 15.3 months (range 14-18 months) and outcomes were evaluated radiographically and clinically (Visual Analogue Scale (VAS) and Oswestry Disability Index (ODI).

RESULTS

The mean operative time was 52 minutes with minimal blood loss in all cases. Fourteen of the 15 patients were discharged to home on the day of their surgery. The mean ODI and leg VAS scores improved from 22.9 ± 3.2 to 12.9 ± 2.7 (p < 0.005), and from 8.6 ± 1.6 to 2.1 + 0.4 (p < 0.005), respectively.

CONCLUSIONS

After an average of 15.3 months of follow-up, the clinical and radiographic results of full endoscopic surgical treatment of single level multi-focal (subarticular as well as far-lateral and/or paracentral) disc herniations are excellent. This study is a case series with mid-term follow-up (Level IV).

CLINICAL RELEVANCE

Foraminal and extra-foraminal full endoscopic decompression appears to offer a safe minimally invasive solution to a complex pathologic problem.

Dorsal spanning plate fixation for distal radius fractures

In polytrauma patients, the presence of a multifragmentary distal radius fracture poses a challenge with respect to early mobilization. Dorsal spanning plate fixation is an alternative choice for these patients for providing definitive operative fixation of the distal radius fracture and for providing a construct to allow weight-bearing through the injured wrist for rehabilitative purposes. In this article, we describe the operative technique to place a dorsal spanning plate and provide a retrospective review of outcomes in polytrauma patients.

'Disk shedding' in the cone outer segments of the teleost, Poecilia reticulata P

Electron microscopical observations show that the cones in the retina of the diurnal Poecilia reticulata shed their membranous outer segment disks. This occurs at the side of the disk which is open to the extracellular space. Shedding is observed in single and twin cones and occurs at any level of the outer segment. The disks are not discarded in packages or as single disks, but are shed in small vesicular portions. This mode of 'disk shedding' may explain why in cone outer segments radioactively labelled replacement protein is diffusely distributed.

The accessory outer segment of rods and cones in the retina of the guppy, Poecilia reticulata P. (Teleostei). An electron microscopical study

The ultrastructure of the accessory outer segment (AOS)--a cilium-like structure emanating from the inner segment and running alongside the outer segment of photoreceptors--is described. The AOS occurs in both rods and cones of Poecilia reticulata. Its ultrastructure, including the arrangement of microtubules, which originate from the ciliary stalk, is the same in rods and cones. The cone-AOS is connected with the outer segment by a thin plasmabridge, whereaa the rod-AOS lies embedded within the outer segment. The outer segment of the cone, in contrast to that of the rod, is separated from the pigment epithelium by a large extracellular space. An intimate contact, however, is secured by the AOS; its membrane is closely appositioned to the pigment epithelium membrane. The functional significance of the AOS and its possible occurrence in other vertebrate classes, are discussed.