Minimally invasive surgery for intradural extramedullary spinal cord pathologies: A case series and technical note.

BACKGROUND: Intradural spinal cord pathologies have traditionally been managed with open surgical procedures and require the completion of a durotomy. Minimally invasive techniques are emerging as alternative procedures with the goal of reducing complications, but often require specialized equipment with additional training. METHODS: We conduct a single institution retrospective review from 2016 to 2019 of patients undergoing minimally invasive durotomy closure for intradural extramedullary pathologies using a novel technique that utilizes standard operating room equipment. This cohort is compared to a cohort of patients treated with a traditional open approach. RESULTS: Patients treated with minimally invasive surgery (MIS) had no statistically significant differences in baseline characteristics compared to patients treated with open procedures. Patients treated with MIS had decreases in complication rates, estimated blood loss, and length of stay in the hospital compared to the patients treated with open procedures, but these differences did not reach levels of statistical significance. CONCLUSIONS: Our novel MIS technique for intradural extramedullary pathologies appears to be safe and effective in creating a watertight dural closure using standard operating room equipment, while avoiding the costs and training associated with specialized equipment and possibly improving surgical outcome measures when compared to open approaches.

Comparison of Clinical and Radiographic Outcomes After Standalone Versus Cage and Plate Constructs for Anterior Cervical Discectomy and Fusion.

BACKGROUND: Anterior cervical discectomy and fusion (ACDF) has conventionally been performed using an allograft cage with a plate-and-screw construct. Recently, standalone cages have gained popularity due to theorized decreases in operative time and postoperative dysphagia. Few studies have compared these outcomes. Here, we directly compare the outcomes of plated versus standalone ACDF constructs. METHODS: A single-center retrospective review of patients undergoing ACDF after June 2011 with at least 6 months of follow up was conducted. Clinical outcomes were analyzed and compared between standalone and plated constructs. Multivariate regression analysis of the primary outcome, need for revision surgery, as well as several secondary outcomes, procedure duration, estimated blood loss (EBL), length of hospital stay, disposition, and incidence of dysphagia, hoarseness, or surgical site infection, was completed. RESULTS: A total of 321 patients underwent ACDF and met inclusion-exclusion criteria, with mean follow-up duration of 20 months. Forty-six (14.3%) patients received standalone constructs, while 275 (85.7%) received plated constructs. Fourteen (4.4%) total revisions were necessary, 4 in the standalone group and 10 in the plated group, yielding revision rates of 8.7% and 3.6%, respectively (P = .125). Mean EBL was 98 mL in the standalone group and 63 mL in the plated group (P = .001). Mean procedure duration was 147 minutes in the standalone group and 151 minutes in the plated group (P = .800). Mean hospital stay was 3.6 days in the standalone group and 2.5 days in the plated group (P = .270). There was no significant difference in incidence of dysphagia (P = .700) or hoarseness (P = .700). CONCLUSIONS: Standalone ACDF demonstrates higher, but not statistically significant, revision rates than plate-and-screw constructs, without the hypothesized decreased incidence of dysphagia or hoarseness and without decreased procedure duration or EBL. Surgeons may consider limiting use of these constructs to cases of adjacent segment disease. Larger studies with longer follow up are necessary to make more definitive conclusions. LEVEL OF EVIDENCE: 4. CLINICAL RELEVANCE: This study will help spine surgeons decide between using standalone or cage-and-plate constructs for ACDF.

Arteriovenous Malformations Treated With Frameless Robotic Radiosurgery Using Non-Invasive Angiography: Long-Term Outcomes of a Single Center Pilot Study.

OBJECTIVE: CT-guided, frameless robotic radiosurgery is a novel radiotherapy technique for the treatment of intracranial arteriovenous malformations (AVMs) that serves as an alternative to traditional catheter-angiography targeted, frame-based methods. METHODS: Patients diagnosed with AVMs who completed single fraction frameless robotic radiosurgery at Medstar Georgetown University Hospital between July 20, 2006 - March 11, 2013 were included in the present study. All patients received pre-treatment planning with CT angiogram (CTA) and MRI, and were treated using the CyberKnife radiosurgery platform. Patients were followed for at least four years or until radiographic obliteration of the AVM was observed. RESULTS: Twenty patients were included in the present study. The majority of patients were diagnosed with Spetzler Martin Grade II (35%) or III (35%) AVMs. The AVM median nidus diameter and nidal volume was 1.8 cm and 4.38 cc, respectively. Median stereotactic radiosurgery dose was 1,800 cGy. After a median follow-up of 42 months, the majority of patients (81.3%) had complete obliteration of their AVM. All patients who were treated to a total dose of 1800 cGy demonstrated complete obliteration. One patient treated at a dose of 2,200 cGy developed temporary treatment-related toxicity, and one patient developed post-treatment hemorrhage. CONCLUSIONS: Frameless robotic radiosurgery with non-invasive CTA and MRI radiography appears to be a safe and effective radiation modality and serves as a novel alternative to traditional invasive catheter-angiography, frame-based methods for the treatment of intracranial AVMs. Adequate obliteration can be achieved utilizing 1,800 cGy in a single fraction, and minimizes treatment-related side effects.

Success and Failure of Percutaneous Minimally Invasive Direct Pars Repair: Analysis of Fracture Morphology.

BACKGROUND: Spondylolysis is a defect in the pars interarticularis that typically presents with axial back pain. Recently, minimally invasive spine techniques have increased in popularity and have been applied to the Buck technique of direct pars repair. CASE DESCRIPTION: In our series, 2 patients underwent minimally invasive direct pars repair by the percutaneous insertion of a cannulated lag screw across the pars defect with compression against the lamina. The defect was then decorticated and packed with bone grafting material through a tubular retractor. The clinical records, including preoperative imaging characteristics and intraoperative variables, were collected. The first patient was a 22-year-old woman with bilateral pars defects, and the second was a 21-year-old woman with a left-sided pars defect. They underwent minimally invasive direct pars repair without complications and were discharged home within 24-48 hours. In the first patient, the fusion was successful; however, the second experienced screw back out and required subsequent revision. The follow-up period was 25 months for patient 1 and 21 months for patient 2. The fracture morphology differed. The successfully repaired fractures were linear with smooth cortical edges and oriented perpendicular to the screw trajectory. The failed repair involved a unilateral, curved defect with comminuted cortical edges. CONCLUSION: Minimally invasive direct pars repair can be performed safely and effectively with shortened hospital stays and reduced morbidity. Fracture morphology and orientation could be important predictors of the success of surgery.