Jotham Manwaring

Management of sagittal balance in adult spinal deformity with minimally invasive anterolateral lumbar interbody fusion: a preliminary radiographic study

OBJECT Minimally invasive (MI) fusion and instrumentation techniques are playing a new role in the treatment of adult spinal deformity. The open pedicle subtraction osteotomy (PSO) and Smith-Petersen osteotomy (SPO) are proven segmental methods for improving regional lordosis and global sagittal parameters. Recently the MI anterior column release (ACR) was introduced as a segmental method for treating sagittal imbalance. There is a paucity of data in the literature evaluating the alternatives to PSO and SPO for sagittal balance correction. Thus, the authors conducted a preliminary retrospective radiographic review of prospectively collected data from 2009 to 2012 at a single institution. The objectives of this study were to: 1) investigate the radiographic effect of MI-ACR on spinopelvic parameters, 2) compare the radiographic effect of MI-ACR with PSO and SPO for treatment of adult spinal deformity, and 3) investigate the radiographic effect of percutaneous posterior spinal instrumentation on spinopelvic parameters when combined with MI transpsoas lateral interbody fusion (LIF) for adult spinal deformity. METHODS Patient demographics and radiographic data were collected for 36 patients (9 patients who underwent MI-ACR and 27 patients who did not undergo MI-ACR). Patients included in the study were those who had undergone at least a 2-level MI-LIF procedure; adequate preoperative and postoperative 36-inch radiographs of the scoliotic curvature; a separate second-stage procedure for the placement of posterior spinal instrumentation; and a diagnosis of degenerative scoliosis (coronal Cobb angle > 10° and/or sagittal vertebral axis > 5 cm). Statistical analysis was performed for normality and significance testing. RESULTS Percutaneous transpedicular spinal instrumentation did not significantly alter any of the spinopelvic parameters in either the ACR group or the non-ACR group. Lateral MI-LIF alone significantly improved coronal Cobb angle by 16°, and the fractional curve significantly improved in a subgroup treated with L5-S1 transforaminal lumbar interbody fusion. Fifteen ACRs were performed in 9 patients and resulted in significant coronal Cobb angle correction, lumbar lordosis correction of 16.5°, and sagittal vertebral axis correction of 4.8 cm per patient. Segmental analysis revealed a 12° gain in segmental lumbar lordosis and a 3.1-cm correction of the sagittal vertebral axis per ACR level treated. CONCLUSIONS The lateral MI-LIF with ACR has the ability to powerfully restore lumbar lordosis and correct sagittal imbalance. This segmental MI surgical technique boasts equivalence to SPO correction of these global radiographic parameters while simultaneously creating additional disc height and correcting coronal imbalance. Addition of posterior percutaneous instrumentation without in situ manipulation or overcorrection does not alter radiographic parameters when combined with the lateral MI-LIF.

Neuroendoscopic stent placement for cerebrospinal fluid pathway obstructions in adults

OBJECTIVE Since its revival in the early 1990s, neuroendoscopy has become an integral component of modern neurosurgery. Endoscopic stent placement for treatment of CSF pathway obstruction is a rarely used and underestimated procedure. The authors present the first series of neuroendoscopic intracranial stenting for CSF pathway obstruction in adults with associated results and complications spanning a long-term follow-up of 20 years. METHODS The authors retrospectively reviewed a prospectively maintained clinical database for endoscopic stent placement performed in adults between 1993 and 2013. RESULTS Of 526 endoscopic intraventricular procedures, stents were placed for treatment of CSF disorders in 25 cases (4.8%). The technique was used in the management of arachnoid cysts (ACs; n = 8), tumor-related CSF disorders (n = 13), and hydrocephalus due to stenosis of the foramen of Monro (n = 2) or aqueduct (n = 2). The mean follow-up was 87.1 months. No deaths or infections occurred that were related to endoscopic placement of intracranial stents. Late stent dislocation or migration was observed in 3 patients (12%). CONCLUSIONS Endoscopic intracranial stent placement in adults is rarely required but is a safe and helpful technique in select cases. It is indicated when reliable and long-lasting restoration of CSF pathway obstructions cannot be achieved with standard endoscopic techniques. In the treatment of tumor-related hydrocephalus, it is a good option to avoid reclosure of the restored CSF pathway by tumor growth. Currently, routine stent placement after endoscopic fenestration of ACs is not recommended. Stent placement for treatment of CSF disorders due to tumor is a good option for avoiding CSF shunting. To avoid stent migration and dislocation, and to allow for easy removal if needed, the device should be fixed to a bur hole reservoir.

The small-chamber irrigation technique (SCIT): a simple maneuver for managing intraoperative hemorrhage during endoscopic intraventricular surgery.

BACKGROUND: Acute intraoperative intraventricular hemorrhage is a feared event in endoscopic neurosurgical procedures. OBJECTIVE: To describe the small-chamber irrigation technique (SCIT) for intraoperative endoscopic management of intraventricular hemorrhage. METHODS: The SCIT was used in intraventricular surgery for hydrocephalus, intraventricular tumors requiring biopsy, arachnoid cysts, and colloid cysts. RESULTS: Intraventricular hemorrhage was successfully managed endoscopically with a combination of the SCIT, routine irrigation, and coagulation, allowing for completion of the primary procedures. CONCLUSION: The SCIT is a powerful tool that the neuroendoscopist can use for visualization to achieve hemostasis when performing intraventricular endoscopic surgery. ABBREVIATIONS: SCIT, small-chamber irrigation technique

Primary leptomeningeal melanoma of the cervical spine mimicking a meningioma-a case report.

Background and Importance Primary leptomeningeal melanoma (PLM) is highly malignant and exceedingly rare. Due to its rarity, diagnostic and treatment paradigms have been slow to evolve. We report the first case of a PLM that mimics a cervical spine meningioma and then discuss the current clinical, radiologic, and pathologic diagnostic methodologies as well as expected outcomes related to this disease. Clinical Presentation A 54-year-old woman presented a dural-based extramedullary solid mass ventral to the C2–C3 spinal cord causing spinal cord compression without cord signal changes, characteristic of meningioma. Intraoperative microscopic inspection revealed numerous black spots littering the surface of the dura; the tumor itself was yellow in appearance and had a soft consistency. Pathologic analysis of the specimen revealed a malignant melanin-containing tumor. No primary site was found, so a diagnosis of primary leptomeningeal melanoma was made, and the patient subsequently received interferon therapy. To date (2 years postoperatively), no local or systemic recurrence of the tumor has been identified. Conclusion As with most rare tumors, case reports constitute the vast majority of references to PLM. Only an increased awareness and an extensive report of each individual case can help diagnose and clarify the nature of PLM. Clinicians need to be aware of such malignant conditions when diagnosing benign tumoral lesions of the spine such as meningiomas.

Corpectomy cage subsidence with rectangular versus round endcaps

Corpectomy cages with rectangular endcaps utilize the stronger peripheral part of the endplate, potentially decreasing subsidence risk. The authors evaluated cage subsidence during cyclic biomechanical testing, comparing rectangular versus round endcaps. Fourteen cadaveric spinal segments (T12-L2) were dissected and potted at T12 and L2, then assigned to a rectangular (n=7) or round (n=7) endcap group. An L1 corpectomy was performed and under uniform conditions a cage/plate construct was cyclically tested in a servo-hydraulic frame with increasing load magnitude. Testing was terminated if the test machine actuator displacement exceeded 6mm, or the specimen completed cyclic loading at 2400 N. Number of cycles, compressive force and force-cycles product at test completion were all greater in the rectangular endcap group compared with the round endcap group (cycles: 3027 versus 2092 cycles; force: 1943 N versus 1533 N; force-cycles product: 6162kN·cycles versus 3973 kN·cycles), however these differences were not statistically significant (p ⩾ 0.076). After normalizing for individual specimen bone mineral density, the same measures increased to a greater extent with the rectangular endcaps (cycles: 3014 versus 1855 cycles; force: 1944 N versus 1444 N; force-cycles product: 6040 kN·cycles versus 2980 kN·cycles), and all differences were significant (p⩽0.030). The rectangular endcap expandable corpectomy cage displayed increased resistance to subsidence over the round endcap cage under cyclic loading as demonstrated by the larger number of cycles, maximum load and force-cycles product at test completion. This suggests rectangular endcaps will be less susceptible to subsidence than the round endcap design.

Cranial reduction and fixation with a resorbable plate combined with cerebrospinal fluid shunting for difficult-to-manage macrocephaly related to hydrocephalus.

The management of newborns with extreme macrocephaly related to hydrocephalus can be difficult; balancing the treatment of severe cranial deformity with optimal hydrocephalus management can be complicated. Excessive CSF drainage can result in significant suture overlap that leads to difficulties in patient positioning, secondary synostosis, and long-term aesthetic complications. Delayed cranial reduction and remodeling procedures carry significant risk, and the aesthetic outcomes have sometimes been poor. The authors describe a newborn with severe macrocephaly who underwent shunt placement followed by a limited cranial reduction and fixation procedure using an absorbable plate within the 1st week of life. The procedure produced an immediate intracranial volume reduction of 49%. This novel management strategy facilitated patient positioning, simplified hydrocephalus management, and provided an excellent aesthetic outcome.

Endoscopic Third Ventriculostomy before Posterior Fossa Tumor Surgery in Adult Patients

Objective Obstructive hydrocephalus in patients with posterior fossa tumors is frequently seen. Treatment options include immediate tumor removal or prior cerebrospinal fluid (CSF) diversion procedures. The necessity and feasibility of an ETV in these situations has not yet been proven in adult patients. Methods We retrospectively reviewed our prospectively maintained database for ETVs before surgery of posterior fossa tumors in adults. The primary focus of data analyses was the question of whether the ETV was suitable to treat the acute situation of hydrocephalus without an increased rate of complications due to the special anatomical situation with a posterior fossa tumor. We also analyzed whether any further CSF diverting procedures were necessary. Results A total of 40 adult patients who underwent an ETV before posterior fossa tumor surgery were analyzed. Overall, 33 patients (82.5%) had clinical signs of hydrocephalus, and all of them improved in their clinical course after ETV. Seven patients (17.5%) did not demonstrate clinical signs of hydrocephalus, but ETV was performed with prophylactic or palliative intent in six patients and one patient, respectively. No complications were observed due to ETV itself. No permanent shunting procedure was necessary in a mean follow‐up of 76.5 months. Early additional CSF diverting procedures (redo ETV, external ventricular drain) were performed in five patients (12.5%). Conclusion The present series confirms the feasibility and safety of ETV before posterior fossa tumor surgery in adult patients. If patients had symptomatic hydrocephalus before tumor surgery, an ETV can be performed, followed by early elective tumor surgery. A prophylactic ETV in asymptomatic patients is not advised. Early elective tumor surgery should be performed in these patients.

Accidental intracranial infusion of parenteral nutrition in a preterm neonate

Vascular access in the neonate can be challenging, especially in preterm infants. When other access is not available, superficial scalp veins can be safely used for vascular access. However, rare and potentially catastrophic complications can occur due to unique features of the neonatal skull and soft-tissue anatomy. The authors report a rare complication of vascular access in a preterm infant, which led to the direct infusion of parenteral nutrition into the intracranial space. The child had an excellent outcome after open drainage and irrigation of bilateral intracranial spaces and the spinal thecal sac. Relevant anatomy is illustrated, and an outcome-based literature review is presented on this rarely reported condition. Surgical and conservative management strategies are discussed, along with clinical and radiographic follow-up. Drainage and irrigation is advocated in patients with mass effect, viscous effusions, or declining neurological examination findings.

The guillotine knife: a novel tool for safe endoscopic cutting of intracranial membranes.

This article describes a new endoscopic cutting tool that acts like a guillotine. It enables safe cutting of membranes overlying neurovascular structures because the footplate protects these structures from inadvertent injury. The footplate is introduced under the membrane, elevating it slightly, and then the membrane is cut while pushing the blade down into the footplate. The guillotine knife has been used in various endoscopic procedures such as septostomies, arachnoid cyst fenestrations, colloid cysts resections, and fenestrations of other intraventricular membranes. The authors think that the guillotine knife is a useful addition to the neuroendoscopic armamentarium.