Tarlov Cyst Causing Sacral Insufficiency Fracture

BACKGROUND AND IMPORTANCE

Tarlov cysts, also known as perineural cysts, have been described as meningeal dilations of the spinal nerve root sheath between the peri- and endoneurium at the dorsal root ganglion. Most often they are found in the sacrum involving the nerve roots. Normally asymptomatic, they have been reported to present with radiculopathy, paresthesias, and even urinary or bowel dysfunction. Sacral insufficiency has not been a well-documented presentation.

CLINICAL PRESENTATION

The patient is a 38-year-old female who started to develop left low back pain and buttock pain that rapidly progressed into severe pain with some radiation down the posterior aspect of her left leg. There was no recent history of spine or pelvic trauma. These symptoms prompted her initial emergency department evaluation, and imaging demonstrated a large Tarlov cyst with an associated sacral insufficiency fracture. She was noted to have a normal neurological examination notable only for an antalgic gait. She was taken to surgery via a posterior approach and the cyst was identified eccentric to the left. The cyst was fenestrated and the nerve roots identified. Given her large area of bone erosion and insufficiency fractures, fixation of the sacroiliac joints was deemed necessary. Fusion was extended to the L5 vertebral body to buttress the fixation. She tolerated the procedure well and was discharged from the hospital on postoperative day 3.

CONCLUSION

Tarlov cysts of the sacrum can lead to significant bone erosion and subsequent insufficiency fractures, requiring fenestration and in some cases, complex sacropelvic fixation.

Does patient selection account for the perceived cost savings in outpatient spine surgery? A meta-analysis of current evidence and analysis from an administrative database

OBJECTIVE

From 1994 to 2006 outpatient spinal surgery increased 5-fold. The perceived cost savings with outcomes comparable to or better than those achieved with inpatient admission for the same procedures are desirable in an era where health expenditures are scrutinized. The increase in outpatient spine surgery is also driven by the proliferation of ambulatory surgery centers. In this study, the authors hypothesized that the total savings in outpatient spine surgery is largely driven by patient selection and biases toward healthier patients.

METHODS

A meta-analysis assessed patient selection factors and outcomes associated with outpatient spine procedures. Pooled odds ratios and mean differences were calculated using a Bayesian random-effects model. The authors extended this analysis in a novel way by using the results of the meta-analysis to examine cost data from an administrative database of academically affiliated hospitals. A Bayesian approach with priors informed by the meta-analysis was used to compare costs for inpatient and outpatient performance of anterior cervical discectomy and fusion (ACDF) and lumbar laminectomy.

RESULTS

Sixteen studies with a total of 370,195 patients met the inclusion criteria. Outpatient procedures were associated with younger patient age (mean difference [MD] −2.34, 95% credible interval [CrI] −4.39 to −0.34) and no diabetes diagnosis (odds ratio [OR] 0.78, 95% CrI 0.54–0.97). Outpatient procedures were associated with a lower likelihood of reoperation (OR 0.42, 95% CrI 0.16–0.80), 30-day readmission (OR 0.39, 95% CrI 0.16–0.74), and complications (OR 0.29, 95% CrI 0.15–0.50) and with lower overall costs (MD −$121,392.72, 95% CrI −$216,824.81 to −$23,632.92). Additional analysis of the national administrative data revealed more modest cost savings than those found in the meta-analysis for outpatient spine surgeries relative to inpatient spine surgeries. Estimated cost savings for both younger patients ($555 for those age 30–35 years [95% CrI −$733 to −$374]) and older patients ($7290 for those age 65–70 years [95% CrI −$7380 to −$7190]) were less than the overall cost savings found in the meta-analysis.

CONCLUSIONS

Compared to inpatient spine surgery, outpatient spine surgery was associated with better short-term outcomes and an initial reduction in direct costs. A selection bias for outpatient procedures toward younger, healthier patients may confound these results. The additional analysis of the national database suggests that cost savings in the outpatient setting may be less than previously reported and a result of outpatient procedures being offered more frequently to younger and healthier individuals.

Understanding the Impact of Obesity on Short-term Outcomes and In-hospital Costs After Instrumented Spinal Fusion

BACKGROUND

Obesity rates continue to rise along with the number of obese patients undergoing elective spinal fusion.

OBJECTIVE

To evaluate the impact of obesity on resource utilization and early complications in patients undergoing surgery for degenerative spine disease.

METHODS

A single-institution retrospective analysis was conducted on patients with degenerative spine disease requiring instrumentation between 2008 and 2012. The 801 identified patients were grouped based on a body mass index (BMI) of <30 (nonobese, n = 478), ≥30 and <40 (obese, n = 283), and alternatively BMIs of ≥40 (morbidly obese, n = 40). Baseline characteristics, surgical outcomes and requirements, complications, and cost were compared. Logistic and linear regression analyses were used to determine the strength of association between obesity and outcomes for categorical and continuous data, respectively.

RESULTS

Significant differences were found in comorbidities between cohorts. Multivariate analysis revealed significant associations between obesity and longer anesthesia times (30 minutes, P = .008), and surgical times (24 minutes, P = .02). Additionally, there was a 2.8 times higher rate of wound complications in obese patients (4.2% vs 1.5, P = .03), and 2.5 times higher rate of major medical complications (7.8% vs 3.1, P = .01). Morbid obesity resulted in a 10 times higher rate of wound complications (P < .001). Morbid obesity resulted in a $9078 (P = .005) increase in overall cost of care.

CONCLUSION

Increased BMI is associated with longer operative times, increased complication rates, and increased cost independent of comorbidities. These effects are more pronounced with morbidly obese patients, further supporting a role for preoperative weight loss.

Multiple mechanisms control the expression of granulocyte-macrophage colony-stimulating factor by human fibroblasts

Human granulocyte-macrophage colony-stimulating factor (GM-CSF) has in vitro and in vivo effects on hemopoiesis and enhances the function of circulating mature myeloid cells. Unstimulated fibroblasts show low level GM-CSF transcription but no accumulation of GM-CSF mRNA or protein, whereas fibroblasts stimulated by TNF-alpha, IL-1, and phorbol diester have been shown to produce and secrete GM-CSF. To determine the mechanisms controlling the expression of GM-CSF in human fibroblasts, we used a transient transfection assay to look at the effect of TNF-alpha, IL-1 and phorbol diester on GM-CSF promoter sequences. Our results demonstrate that the phorbol diester, 12-O-tetradecanoylphorbol 13-acetate, can stimulate GM-CSF transcription via sequences located within 53 bp upstream of the GM-CSF cap site. TNF-alpha and IL-1 had no effect on GM-CSF transcription, suggesting that these cytokines act predominantly post-transcriptionally to stimulate production of GM-CSF. Our results demonstrate that multiple mechanisms can be used by human fibroblasts to produce GM-CSF in response to various inflammatory stimuli.

Multiple mechanisms control the expression of granulocyte-macrophage colony-stimulating factor by human fibroblasts

Human granulocyte-macrophage colony-stimulating factor (GM-CSF) has in vitro and in vivo effects on hemopoiesis and enhances the function of circulating mature myeloid cells. Unstimulated fibroblasts show low level GM-CSF transcription but no accumulation of GM-CSF mRNA or protein, whereas fibroblasts stimulated by TNF-alpha, IL-1, and phorbol diester have been shown to produce and secrete GM-CSF. To determine the mechanisms controlling the expression of GM-CSF in human fibroblasts, we used a transient transfection assay to look at the effect of TNF-alpha, IL-1 and phorbol diester on GM-CSF promoter sequences. Our results demonstrate that the phorbol diester, 12-O-tetradecanoylphorbol 13-acetate, can stimulate GM-CSF transcription via sequences located within 53 bp upstream of the GM-CSF cap site. TNF-alpha and IL-1 had no effect on GM-CSF transcription, suggesting that these cytokines act predominantly post-transcriptionally to stimulate production of GM-CSF. Our results demonstrate that multiple mechanisms can be used by human fibroblasts to produce GM-CSF in response to various inflammatory stimuli.