Kyphoplasty of C2 Pathological Fractures Using an Anterior Midline Approach and Steerable Osteotome: Technical Note and Case Series.

BACKGROUND: Malignant lesions involving the C2 vertebral body (axis) may be challenging to treat, and not all patients with cancer are good candidates for posterior cervical or occipitocervical instrumentation. OBJECTIVE: To describe a modified technique of the direct anterolateral C2 kyphoplasty using a steerable osteotome, commonly used for the treatment of thoracolumbar spinal lesions. We also report a case series of 11 patients treated with this technique at our institution. METHODS: The authors performed a retrospective review of all patients who underwent a C2 kyphoplasty using the anterior midline approach from 2010 to 2020. Patient demographics, tumor characteristics, pain severity (visual analog scale), Karnofsky performance status , perioperative complications, and postoperative spinal stability were assessed. RESULTS: The main indication for a C2 kyphoplasty was refractory neck pain. All patients tolerated the procedure well. There were no intraoperative complications. One patient developed transient dysphagia. Visual analog scale scores were 9.00 ± 1.10 preoperative and 3.73 ± 1.85 at 2 weeks and 1.67 ± 1.66 at 3 months after the procedure and continued to stay low during the remainder of the follow-up (4-60 months). The Karnofsky performance status improved from 72.73 ± 11.04 preoperatively to 82.22 ± 8.33 at 2 weeks and 86.67 ± 5.00 at 3 months after the procedure. There was no evidence of new occurrence or progression of C2 fractures. CONCLUSION: The anterior kyphoplasty using a steerable osteotome for tumors of the axis can result in lasting pain reduction and improved cervical stability while demonstrating a low complication rate.

Case report: bilateral tunneled epidural catheters to prevent unilateral analgesia for cancer-related pain.

OBJECTIVE: Unilateral analgesia often occurs with epidural analgesia. Traditional methods of troubleshooting this problem can be insufficient in obtaining adequate pain relief in a timely manner for terminal cancer patients. This case report demonstrates a safe and effective solution which can be utilized in these circumstances. CASE REPORT: A 55-year-old female with stage IV pancreatic cancer and life expectancy of a few weeks presented to the interventional pain clinic with intractable sacral pain. The decision to place an epidural catheter and external pump for analgesia was made. An epidural catheter placed at the L5-S1 level showed contrast spread only along the right nerve roots and a test dose produced only right-sided analgesia. Suspecting compartmentalization of the epidural space, a second left-sided epidural catheter was placed and bilateral analgesia was achieved by using both catheters. This dual catheter technique gave the patient effective bilateral analgesia until she passed away several weeks later. CONCLUSION: The bilateral epidural catheter technique is safe and effective in patients who present with persistent unilateral epidural analgesia despite exhausting traditional solutions.

Intrathecal Injection of Gadobutrol: A Tale of Caution.

In the field of interventional pain medicine a radiocontrast agent is commonly used in conjunction with fluoroscopy. Limited work has been published regarding the use of gadolium based contrast agents (GBCA) in the intrathecal space. We report a case of an intrathecal gadobutrol injection resulting in neurotoxic manifestations.A 60-year-old female with a history significant for lumbar post-laminectomy syndrome and intrathecal drug delivery implantation was admitted for lumbar fusion and kyphoplasty. Postoperatively, the patient had escalating pain medication requirements. A pump and intrathecal catheter contrast study was completed to assess the integrity and proper placement of the intrathecal catheter. Due to patient.s allergy to iodinated contrast, the physician requested gadolinium contrast dye. Unknown to the staff was that Magnevist had recently been replaced with an alternative GBCA, Gadavist (gadobutrol). 2 cc of Gadavist was injected. The catheter was determined to be intact and in proper position. Less than five minutes after the injection of gadobutrol, the patient reported spastic pain of the lower extremities. There is a lack of evidence as it relates to the use of GBCA specifically gadobutrol in the intrathecal space. The use of gadobutrol in the intrathecal space should be used with caution.

Formal total syntheses of classic natural product target molecules via palladium-catalyzed enantioselective alkylation.

Pd-catalyzed enantioselective alkylation in conjunction with further synthetic elaboration enables the formal total syntheses of a number of "classic" natural product target molecules. This publication highlights recent methods for setting quaternary and tetrasubstituted tertiary carbon stereocenters to address the synthetic hurdles encountered over many decades across multiple compound classes spanning carbohydrate derivatives, terpenes, and alkaloids. These enantioselective methods will impact both academic and industrial settings, where the synthesis of stereogenic quaternary carbons is a continuing challenge.

Palladium-catalyzed decarboxylative allylic alkylation of diastereomeric ß-ketoesters.

The palladium-catalyzed decarboxylative allylic alkylation of diastereomeric ß-ketoesters derived from 4-tert-butylcyclohexanone is described. These experiments were performed to elucidate our understanding of stereoablative enantioconvergent catalysis. A detailed analysis of the product distribution, including stereochemical outcome of the products, is included. These studies also reveal an interesting example of selectivity that is governed by competing modes of substrate and catalyst control.

Development of (trimethylsilyl)ethyl ester protected enolates and applications in palladium-catalyzed enantioselective allylic alkylation: intermolecular cross-coupling of functionalized electrophiles.

The development of (trimethylsilyl)ethyl ester protected enolates is reported. The application of this class of compounds in palladium-catalyzed asymmetric allylic alkylation is explored, yielding a variety of α-quaternary six- and seven-membered ketones and lactams. Independent coupling partner synthesis engenders enhanced allyl substrate scope relative to traditional ß-ketoester substrates; highly functionalized α-quaternary ketones generated by the union of (trimethylsilyl)ethyl ß-ketoesters and sensitive allylic alkylation coupling partners serve to demonstrate the utility of this method for complex fragment coupling.

Enantio-, diastereo-, and regioselective iridium-catalyzed asymmetric allylic alkylation of acyclic ß-ketoesters.

The first regio-, diastereo-, and enantioselective allylic alkylation of acyclic ß-ketoesters to form vicinal tertiary and all-carbon quaternary stereocenters is reported. Critical to the successful development of this method was the employment of iridium catalysis in concert with N-aryl-phosphoramidite ligands. Broad functional group tolerance is observed at the keto-, ester-, and α-positions of the nucleophile. Various transformations demonstrating the utility of this method for rapidly accessing complex enantioenriched compounds are reported.

Construction of vicinal tertiary and all-carbon quaternary stereocenters via Ir-catalyzed regio-, diastereo-, and enantioselective allylic alkylation and applications in sequential Pd catalysis.

Highly congested vicinal stereocenters comprised of tertiary and all-carbon quaternary centers were generated via Ir-catalyzed asymmetric allylic alkylation of ß-ketoesters. These catalytic reactions proceed in excellent yields with a broad scope on either reaction partner and with outstanding regio-, diastereo-, and enantiocontrol. Implementation of a subsequent Pd-catalyzed alkylation affords dialkylated products with pinpoint stereochemical control of both chiral centers.