Anterior approach to cervical intramedullary pilocytic astrocytoma

Transpedicular Approach for Ventral Epidural Abscess Evacuation in the Cervical Spine

OBJECTIVE

Spinal epidural abscess may require prompt surgical intervention. Ventral cervical abscesses pose a particular challenge regarding the approach for surgical evacuation. The aim of this article was to describe the technical nuances of a posterior transpedicular cervical approach for evacuation of a ventral epidural abscess.

METHODS

After a standard laminectomy, a foraminotomy was performed to identify the exiting nerve root. Then the medial aspect of the pedicle below the nerve was drilled. This allowed the insertion of a dissector to reach the ventral epidural space and drain the contents in conjunction with suction and irrigation. The posterolateral aspect of the superior endplate of the respective vertebra could be further drilled at this point, allowing access to the disc space with minimal retraction of the exiting nerve root.

RESULTS

Two patients underwent emergent evacuation of a ventral epidural abscess in the cervical spine using this technique. Radiographic and clinical improvement was evident after evacuation of the abscesses in both cases.

CONCLUSIONS

Access to the ventral epidural space is feasible using a transpedicular approach in the cervical spine for evacuation of an epidural abscess.

Primary spinal pilocytic astrocytoma: clinical study with long-term follow-up in 16 patients and a literature review

Primary pilocytic astrocytoma (PA) of the spine is extremely rare and most published case series only include only a few patients. We attempted to explore the clinical features, radiological findings, and treatment outcomes of patients with spinal PA. Sixteen spinal PA patients who were surgically treated in our hospital between April 2008 and June 2018 were included in this retrospective study. An integrative analysis was performed regarding spinal PA patients by extracting from published studies on PubMed. The 16 patients with spinal PA included eight male and eight female patients with a mean age of 29.1 years. Ten cases (62.5%) had masses located in the cervical segments, five (31.3%) had masses in the thoracic segments, and one (6.2%) had masses in the sacral canal. All the patients were treated surgically with 13 gross total resections (GTRs, 81.3%) and three subtotal resections (STRs). The mean follow-up period was 40.4 months. These tumors accounted for a recurrence rate of 37.5% (6 of 16 patients) and no death during the follow-up periods. The influencing factors of recurrence were mainly STR, gene mutation (NF-1 and H2-K27M), and the number of segments involved. The mean recurrence-free survival duration was 19 months. The imaging features of spinal PA are heterogeneous, and the definitive diagnosis requires pathological support. GTR is the standard therapy for spinal PAs, although patients with GTR are still likely to relapse. The regular spinal magnetic resonance imaging follow-ups are required regardless of the resection status. Reoperation is feasible for patients with recurrence.

Intradural spinal tumors in adults-update on management and outcome

Among spinal tumors that occur intradurally, meningiomas, nerve sheath tumors, ependymomas, and astrocytomas are the most common. While a spinal MRI is the state of the art to diagnose intradural spinal tumors, in some cases CT scans, angiography, CSF analyses, and neurophysiological examination can be valuable. The management of these lesions depends not only on the histopathological diagnosis but also on the clinical presentation and the anatomical location, allowing either radical resection as with most extramedullary lesions or less invasive strategies as with intramedullary lesions. Although intramedullary lesions are rare and sometimes difficult to manage, well-planned treatment can achieve excellent outcome without treatment-related deficits. Technical advances in imaging, neuromonitoring, minimally invasive approaches, and radiotherapy have improved the outcome of intradural spinal tumors. However, the outcome in malignant intramedullary tumors remains poor. While surgery is the mainstay treatment for many of these lesions, radiation and chemotherapy are of growing importance in recurrent and multilocular disease. We reviewed the literature on this topic to provide an overview of spinal cord tumors, treatment strategies, and outcomes. Typical cases of extra- and intramedullary tumors are presented to illustrate management options and outcomes.

Dorsal root entry zone approach in ventral and eccentric intramedullary tumors: A report of 2 cases

Intramedullary tumors constitute 2-4% of all the tumors affecting the central nervous system. They include low-grade astrocytomas and ependymomas in majority. Earlier, only biopsy or decompression used to be the best available options for these tumors, but with the upcoming technology and newer techniques, gross total excision with the aim of achieving complete removal has been the preferred treatment for these tumors. Usually, nearly all intramedullary tumors are approached from posterior midline myelotomy as this is the safest corridor to approach under neurophysiologic monitoring. But sometimes, if the tumor is exophytic, eccentric, or ventral to the cord, other routes of access may also be useful. These approaches are less frequently used these days and actually may be found useful in certain cases. Hence, they should not be termed “obsolete” and must be kept in mind for tumors in specific location. We describe a similar less commonly used dorsal root entry zone approach for near total excision of ventral and eccentric cervical pilocytic astrocytomas in two patients.

Surgical management of ventral intradural spinal lesions

OBJECTIVE

Access to the ventral intradural spinal canal may be required for treatment of a variety of lesions affecting the spinal cord and adjacent intradural structures. Adequate exposure is usually achieved through a standard posterior laminectomy or posterolateral approaches, although formal anterior approaches are used to access lesions in the subaxial cervical spine. Modifications of the standard posterior exposure as well as ventral or ventrolateral approaches are increasingly being used for treating intradural spinal pathologies. In this study, the authors review their experience with 35 consecutive cases of ventral intradural spinal lesions.

METHODS

Only patients with intradural lesions located completely ventral to the dentate ligament attachments were included in this retrospective study. Patients with the following lesions were excluded from the study: lesions at the level of the filum terminale/cauda equina, lesions with any component that extended dorsally to the dentate ligament, or lesions with extradural extension (that is, dumbbell tumors) below the C-2 level. Between January 2000 and September 2009, a total of 35 patients (age range 17-72 years, mean 42.6 years) with ventral intradural spinal pathology underwent surgery at the authors' institution.

RESULTS

There were 28 intradural extramedullary mass lesions: 15 meningiomas, 12 solitary schwannomas, and 1 neuroenteric cyst. Surgical approaches to these lesions included 23 posterior or posterolateral approaches, 4 anterior approaches with corpectomy followed by tumor resection and reconstruction, and 1 lateral transforaminal resection. No patient had evidence of instability at follow-up, which ranged from 6 months to 8 years in duration. One patient had worsened spinal cord function following surgery. There were 7 patients with intramedullary lesions: 2 hemangioblastomas, 2 cavernous malformations, 2 perimedullary fistulas, and 1 astrocytoma. All but 1 were superficial pia-based lesions arising ventral to the dentate ligament. Five of the 6 pia-based lesions were successfully resected via a standard posterior laminectomy, partial facetectomy with dentate section, and spinal cord rotation. One midline pial lesion was successfully removed with a minimally invasive retropleural thoracotomy. The astrocytoma was resected through an anterior cervical corpectomy, which was followed by instrumented reconstruction. There were no significant complications or neurological morbidity at follow-up (range 9 months-6 years).

CONCLUSIONS

Most intradural spinal lesions can be treated with contemporary microsurgical techniques with long-term control or cure of the lesion and preservation of neurological function. Standard posterior approaches provide adequate exposure to safely remove the vast majority of these lesions without the need for a potentially destabilizing resection of the facet or pedicle. Posterior exposures with varying degrees of lateral bone resection, dentate ligament division, and gentle cord rotation may also provide adequate exposure for safe removal of nonmidline ventrolateral superficial pial presenting spinal cord lesions. Nevertheless, in certain cases of ventral intradural lesions, anterior approaches are necessary and should be considered under appropriate circumstances.