In the context of ocular development and eye growth regulation, retinal defocus and/or image contrast appear key variables although the nature of the signal(s) relayed from the retina to the sclera remains poorly understood. Nonetheless, under optimal visual conditions, eye length is brought into alignment with its optical power to achieve approximate emmetropia, through appropriate adjustment to eye growth. The retinal pigment epithelium (RPE), which lies between the retina and choroid/sclera, appears to play a crucial role in this process. In the investigations reported here, we used a chick model system to assess the threshold duration of exposure to lens-imposed defocus and form-deprivation necessary for conversion of evoked retinal signals into changes in BMP gene expression in the RPE. Our study provides evidence for the following: 1) close-loop, optical defocus-guided (negative and positive lenses) bidirectional BMP gene expression regulation, 2) open-loop, form-deprivation (diffusers)-induced down-regulation of BMP gene expression, and 3) early, transient up-regulation of BMP gene expression in response to both types of lens and diffuser applications. The critical exposure for accurately encoding retinal images as biological signals at the level of the RPE is in the order of minutes to hours, depending on the nature of the visual manipulations.

In the context of ocular development and eye growth regulation, retinal defocus and/or image contrast appear key variables although the nature of the signal(s) relayed from the retina to the sclera remains poorly understood. Nonetheless, under optimal visual conditions, eye length is brought into alignment with its optical power to achieve approximate emmetropia, through appropriate adjustment to eye growth. The retinal pigment epithelium (RPE), which lies between the retina and choroid/sclera, appears to play a crucial role in this process. In the investigations reported here, we used a chick model system to assess the threshold duration of exposure to lens-imposed defocus and form-deprivation necessary for conversion of evoked retinal signals into changes in BMP gene expression in the RPE. Our study provides evidence for the following: 1) close-loop, optical defocus-guided (negative and positive lenses) bidirectional BMP gene expression regulation, 2) open-loop, form-deprivation (diffusers)-induced down-regulation of BMP gene expression, and 3) early, transient up-regulation of BMP gene expression in response to both types of lens and diffuser applications. The critical exposure for accurately encoding retinal images as biological signals at the level of the RPE is in the order of minutes to hours, depending on the nature of the visual manipulations.

Recent studies have demonstrated the defocus sign-dependent, bidirectional gene expression regulation of bone morphogenetic proteins, BMP2, 4 and 7 in chick RPE. In this study, we examined the effects of imposed positive (+10 D) and negative (-10 D) lenses on the gene expression of these BMPs and BMP receptors (BMPR1A, BMPR1B, BMPR2) in chick retina and choroid after monocular lens treatment for 2 or 48 h, as indicators of the roles of retinal and choroidal BMPs and receptors in postnatal eye growth regulation. In retina, although all genes were expressed, neither +10 nor -10 D lenses, worn for either 2 or 48 h, significantly altered gene expression. In contrast, treatment-related differential gene expression was detected in the choroid for both BMPs and their receptors, although interestingly, with the +10 D lens, BMP2 was up-regulated by 156.7 ± 19.7% after 2 h, while BMPR1A was down-regulated to 82.3 ± 12.5% only after 48 h. With the -10 D lens, only the gene expression of BMPR1B was significantly altered, being up-regulated by 162.3 ± 21.2% after 48 h. Untreated birds showed no difference in expression between their two eyes, for any of the genes examined. The finding that retinal gene expression for BMP2, 4, 7 and their receptors are not affected by short-term optical defocus contrasts with previous observations of sign-dependent expression changes for the same genes in the RPE. The latter changes were also larger and more consistent in direction than the choroidal gene expression changes reported here. The interrelationship between these various changes and their biological significance for eye growth regulation are yet to be elucidated.

Study design

Retrospective case series.

Objectives

To evaluate the variability in opioid prescription following primary single-level lumbar microdiscectomy.

Methods

We retrospectively reviewed consecutive patients who underwent primary single-level lumbar microdiscectomy. Only opioid-naïve patients ≥18 years old were included. Patients who had revision microdiscectomy, multilevel decompression, and/or any complication requiring prolonged hospital stay (>2 days) were excluded. The primary outcomes were the maximum daily dosage of opioids prescribed in morphine milligram equivalents (MME) and the number of pills prescribed (equivalent to 5 mg hydrocodone).

Results

Between 2014 and 2019, 169 patients (90 men, 79 women) met inclusion criteria, with a mean age of 46.9 years. Surgery resulted in a statistically significant improvement in VAS (Visual Analogue Scale) score (6.4 to 2.5, P < .01). At discharge, 8 patients (4.7%) did not receive any opioid prescription. Of the remaining 161 patients, 1 patient (0.01%) received hydromorphone, 30 (18.6%) Percocet, 43 (26.7%) oxycodone, and 87 Norco (54.0%). The length of opioid prescription was 6.7 days. The maximum daily dosage of opioids prescribed was 70.4 MME (SD 32.1). The total number of pills prescribed was 89.4 (SD 54.7). Twenty-five patients (15.5%) received a refill prescription. Multivariate analysis demonstrated the operating service, prescriber, and hospital admission were statistically significant predictors of maximum daily MME. The prescriber and hospital admission were statistically significant predictors of total number of pills prescribed.

Conclusions

We found significant variability in opioid prescription following primary single-level lumbar microdiscectomy. For standard spinal procedures like lumbar microdiscectomy, opioid-prescribing guidelines should be established to standardize postoperative pain management.

Study design

Retrospective case series.

Objective

To report our experience with corpectomy of the thoracolumbar (TL) spine through a minimally invasive lateral retropleural or retroperitoneal approach.

Methods

This is a retrospective case series of 20 consecutive patients who underwent minimally invasive TL corpectomy and spinal reconstruction. Electronic medical records were reviewed for demographic, operative, and clinical outcome data.

Results

Between 2015 and 2019, 20 consecutive cases of minimally invasive TL corpectomy were performed, comprising 12 men (60%) and 8 women (40%) with a mean age of 54.3 years. Indications for surgery were infection (n = 6, 30%), metastatic disease (n = 2, 10%), fracture (n = 6, 30%), and calcified disc herniation (n = 6, 30%). Partial and complete corpectomy was performed in 5 patients (25%) and 15 patients (75%), respectively. Mean operative time and estimated blood loss was 276.2 minutes and 558.4 mL, respectively. Mean length of stay from admission and surgery were 14.6 and 11.4 days, respectively. Mean length of stay from surgery for elective cases was 4.2 days. Mean follow-up time was 330.4 days. Visual analogue scale score improved from 7.7 to 4.5 (P < .01). There were a total of 3 postoperative complications in 2 patients, including 1 mortality for urosepsis. One patient had revision spinal surgery for adjacent segment disease.

Conclusions

Corpectomy and reconstruction of the TL spine is feasible and safe using a minimally invasive lateral retropleural or retroperitoneal approach. Since this is a relatively new technique, more studies are needed to compare the short- and long-term radiographic and clinical outcomes between minimally invasive versus open corpectomy of the TL spine.

Study design

Age- and sex-matched cohort study.

Objectives

To compare outcomes after open versus minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF) with bilateral facetectomies.

Methods

We retrospectively compared patients who underwent single- or 2-level MIS-TLIF with an age- and sex-matched open-TLIF cohort. Surgical data was collected for operative time, estimated blood loss (EBL), and drain use. Clinical outcomes included the Visual Analog Scale (VAS), Oswestry Disability Index (ODI), length of stay (LOS), complications, and reoperations. Lumbar radiographs were measured for changes in global lumbar lordosis (LL) and segmental lordosis (SL).

Results

Between 2016 and 2020, 38 MIS-TLIF patients were compared with 38 open-TLIF patients. No subfascial drain was used in the MIS-TLIF group (P < .001). The MIS-TLIF group had longer operative time (310.8 vs 276.5 minutes; P = .046) but less EBL (282.4 vs 420.8 mL; P = .007). LOS (P = .15), complication rates (P = .50), and revision rates (P = .17) were equivalent. VAS and ODI improved but did not differ between groups. In the open-TLIF group, LL and SL were restored or improved in 81.6% and 86.9% of cases, respectively. In the MIS-TLIF group, LL and SL were restored or improved in 86.8% and 97.4% of cases, respectively. There were no differences in changes in LL and SL between groups.

Conclusions

Compared with the age- and sex-matched open-TLIF cohort, patients undergoing MIS-TLIF had reduced EBL and subfascial drain use but increased operative time. There were no differences in complications, reoperations, or LOS. Both groups demonstrated improvement in VAS and ODI. MIS-TLIF with bilateral facetectomies provided equivalent improvements in global and segmental LL.

Background and objectives

Computed tomography (CT) measurements of sarcopenia have been proposed as biomarkers associated with outcomes in various cancers and have typically been evaluated at the L3 vertebral level. However, staging imaging for patients with extremity and truncal soft tissue sarcoma (STS) often only includes chest CT imaging which precludes evaluation at L3. Therefore, we sought to evaluate muscle metrics at T12 on standard staging chest CT scans and evaluate for correlation with overall and event-free survival in patients with STS.

Methods

CT chest imaging for 89 patients with intermediate and high-grade STS (53 male, 36 female; 58.5 ± 19.0 years old, follow-up 37.4 ± 27.1 months) was reviewed on PACS at T12 for skeletal muscle density (SMD) and skeletal muscle index (SMI).

Results

Overall survival increased with increased SMD on univariate (hazard ratio [HR] = 0.61 [0.43, 0.86]) and age-adjusted analysis (HR = 0.65 [0.42, 0.89]. Event-free survival also increased with increased SMD in univariate analyses (HR = 0.68 [0.49, 0.95]) but did not maintain significance after adjusting for age (HR = 0.68 [0.43, 1.07]). SMI was not a predictor of overall or event-free survival.

Conclusions

Higher SMD measured on routinely obtained staging chest CTs in STS patients is associated with improved survival.