Effect of Body Mass Index on Paddle Lead Spinal Cord Stimulator Safety Implantation for Chronic Pain Management.

OBJECTIVE: Spinal cord stimulators (SCS) represent an effective treatment for patients with chronic pain issues. This study examines extremely obese patients (body mass index [BMI] ≥40) as appropriate surgical candidates for paddle lead SCS trial via partial thoracic laminectomy and whether obesity impacts implantation safety. METHODS: A retrospective review of patients treated with partial thoracic laminectomy and paddle lead SCS trial between October 1, 2016 and September 30, 2019 was performed. The primary outcome was implantation safety (complication rate within minimum of 90 days) in patients with extreme obesity (BMI ≥40) compared with patients with BMI <40 and secondary outcome was effectiveness (successful trial leading to final implantation). Seventy-three patients underwent SCS trial. RESULTS: Four (5.48%) patients developed complications with only 1 patient in the BMI ≥40 cohort (not statistically significant). Overall trial success rate was 82.2% (60/73) with statistically significant higher success rates among patients with a BMI ≥40 (93.3% vs. 74.4%, P = 0.0183). CONCLUSIONS: We conclude that paddle lead SCS trial in extremely obese patients is reasonable to offer with the expectation of similar safety concerns as those for patients with a lower BMI.

High-resistance proximal "scaled" ventricular catheters.

PURPOSE: Prove the concept of high-resistance proximal catheters for valve-independent treatment of hydrocephalus. METHODS: A preliminary design process yielded optimal high-resistance proximal ventricular catheters with a "scaled" design and parallel-oriented, U-shaped inlets. Prototypes were manually constructed using carving tools to stamp through silicone tubings. A testing apparatus was developed to simulate cerebrospinal fluid flow through a catheter, and the prototypes were tested against a control catheter for exhibition of an "on/off" phenomenon whereby no flow occurs at low pressures, and flow begins beyond a pressure threshold. Flow distribution was visualized with India ink. Regression analysis was performed to determine linearity. RESULTS: The new designs showed varying amounts of improved flow control with the "scaled" design showing the most practical flow rate control across various pressures, compared to the standard catheter; however, no true "on/off" phenomenon was observed. The "scaled" design showed various degrees of dynamism; its flow rate can be time dependent, and certain maneuvers such as flushing and bending increased flow rate temporarily. Variation in the number of inlets within each "scaled" prototype also affected flow rate. Contrastingly, the flow rate of standard catheters was found to be independent of the number of inlet holes. Ink flow showed even flow distribution in "scaled" prototypes. CONCLUSIONS: This initial feasibility study showed that high-resistance ventricular catheters can be designed to mimic the current/valved system. The "scaled" design demonstrated the best flow control, and its unique features were characterized.

Varicella-Zoster Virus Infection and Osteomyelitis of the Skull.

BACKGROUND: Varicella-zoster virus (VZV) is a common herpesvirus infection that can result in acute varicella/chickenpox, as well as delayed activation in herpes zoster/shingles. Ramsay-Hunt syndrome is a rare presentation of VZV reactivation, involving 1% of cases and resulting in lesion formation along the seventh cranial nerve distribution. We report the first case of a patient who presented with acute calvarial osteomyelitis after VZV reactivation and Propionibacterium acnes suprainfection. CLINICAL PRESENTATION: A 41-year-old man with a history of VZV presented with a 6-month history of chest pain, flulike symptoms, and left-sided headaches. Several concomitant external calvarial lesions were identified, and imaging was concerning for an infectious or neoplastic etiology. The patient underwent surgical debridement, and pathologic samples identified coinfection with P. acnes and VZV. Antibacterial and antiviral therapy resulted in a good outcome. CONCLUSION: Osteomyelitis resulting as a complication of VZV infection is rare, particularly in the calvaria. This is the first reported case of Ramsay-Hunt syndrome-type VZV infection being complicated by osteomyelitis of the calvaria. Our case also demonstrates the diagnosis of VZV osteomyelitis through the use of current pathologic methods.

The role of postnatal neurogenesis in supporting remote memory and spatial metric processing.

In this study, we determined the contribution of juvenile neurogenesis to the performance of mice on a remote memory for temporally based association task and in a novelty based spatial pattern separation task. This was accomplished by mating homozygous DNMT1-loxP mice with heterozygous GFAP-Cre mice and comparing Cre+ (no postnatal neurogenesis) to Cre- (wild type) littermate offspring. The results indicate that Cre+ mice are impaired relative to Cre- mice in the remote memory for a temporal based association task and in a novelty based spatial pattern separation task. These results support the temporal integration model of Aimone et al., [(2006) Nat Neurosci 9:723-727] and provide further support for an important role for postnatally born neurons in spatial pattern separation. In contrast, Cre+ mice are not impaired relative to Cre- mice in an object-context recognition task and a spatial location recognition task. These latter data suggest that postnatally derived neurons in the dentate gyrus (DG) do not support all spatial and object recognition functions of the DG.