Surgical treatment of intramedullary tumors (spinal cord and medulla oblongata). Analysis of 16 cases

Long-Term Recurrent Intramedullary Arachnoid Cyst: Case Report and Literature Review

Objectives  This article reports the management of a case of a 32-year-old male who presented with progressive weakness in the lower limbs and spastic paraparesis secondary to an intramedullary arachnoid cyst (IMAC). For literature review, the authors used the phrase "intramedullary arachnoid cyst" in PubMed search engine. 23 articles describing cases with IMAC were included in this review, with a total of 26 patients. Materials and Methods  We report a case with long term recurrant intramedullary arachnoid cyst and present a review on spinal intramedullary arachnoid cyst. Result  IMAC is showing bimodal incidence and trending to occur below 10 years and after 30 years. However, rarely, it should be considered in the differential diagnosis of intramedullary cystic lesions. Authors suggest doing laminoplasty or fusion for the pediatric patients to prevent kyphoscoliosis deformity in the long run, but doing early surgery to gain better outcome. Resection of the cyst wall should be done as much as possible; if it could not be achieved, then marsupialization or cysto-subarachnoid shunt should be considered. Aspiration alone or fenestration is not enough to eradicate the cyst. Long-term and prospective studies are recommended to achieve the best treatment options. Conclusion  Review supports early surgical treatment of symptomatic IMACs with resection of the cyst wall as much as possible.

Cervicomedullary Gliomas in Pediatric Age: A Systematic Review of the Literature and Tertiary Care Center Experience

INTRODUCTION

Cervicomedullary gliomas (CMGs) are usually low-grade tumors often found in the pediatric age. Histological findings, treatments, and classification have been much the same for 40 years, although histological and molecular classifications have largely been developed for other pediatric CNS tumors. The management and treatment of pediatric CMG are still conducted by many authors according to their anatomical location and characteristics, independently from histology.

METHODS

We conducted a literature review in PubMed (Medline) to identify relevant contributions about pediatric CMG published until December 31, 2021. We also analyzed a series of 10 patients with CMG treated from 2006 to 2021 at IRCCS Istituto Nazionale dei Tumori. The aim of the present review was to see whether and how the diagnosis, treatment, and classification of CMGs in children have developed over time, especially in the context of molecular advancements, and to analyze our single-center experience in the last 15 years.

RESULTS

Thirty articles have been included in the review. Articles have been divided into two historical periods (1981-2000 and 2001-2021) and data from different series were analyzed to see how much the management and treatment of pediatric CMG have changed during years. Analysis of our series of 10 patients affected by CMG was also performed to compare it with the literature.

DISCUSSION

Management and classification of CMG in children have not dramatically changed during years. However, new insight from molecular diagnostics and target therapies and the development of radiological, neurophysiological, and radiotherapy techniques have updated treatment modalities in the last 20 years. Treatment modalities and their innovations have been reviewed and discussed. Further studies are needed to standardize and customize treatment protocols for these tumors.

Treatment of Kyphosis Arising Secondary to Laminectomy and Irradiation in the Pediatric Population

The effects of radiation therapy and laminectomy on the growing spine have been well documented. Due to compromised bone quality after irradiation, spinal fusion has a high failure rate. The aim of this study was to evaluate treatment of post-laminectomy and post-irradiation kyphosis in children using a vascularized rib graft (VRG) to augment anterior spinal fusion and posterior spinal fusion. Data were collected retrospectively from electronic medical records for all patients treated at a single institution for post-laminectomy and post-irradiation kyphosis who underwent VRG to augment spinal fusions done between December 2003 and August 2015. Five patients were included in the analysis. Imaging studies were analyzed by 2 senior pediatric orthopedic surgeons and a pediatric orthopedic surgery fellow. The outcome for all 5 patients who underwent VRG were considered successful at most recent clinical follow-up. Success was defined as the following: complete fusion evident through computed tomography scan, no implant failure, and no kyphosis progression. Follow-up ranged from 21 to 63 months. One patient experienced 2 complications: esophageal tear and deep infection. Spinal fusion with a VRG is a viable treatment option for children who have developed kyphosis following laminectomy and irradiation. On long-term follow-up, there has been no evidence of progression of kyphosis for patients who were treated with VRG in either the primary fusion procedure or in subsequent revision procedures. A VRG provides a non-irradiated, vascularized bone graft to bridge the irradiated segments, increasing the stability of the spine. [Orthopedics. 2021;44(4):e563-e569.].

Sporadic Solid/Cystic Hemangioblastomas in the Cerebellum: Retrospective Study of More Than Ten Years of Experience in a Single Center

BACKGROUND

Solid/cystic hemangioblastomas are rare, and they lack a systematic description. We clarify the epidemiology, clinical features, imaging characteristics, and surgical outcomes of sporadic solid/cystic hemangioblastomas in the cerebellum.

METHODS

A total of 75 patients with sporadic hemangioblastomas from 2006 to 2018 were enrolled in this retrospective study and divided into solid (26/75), cystic (40/75), and solid/cystic (9/75) groups according to the imaging findings. All patients underwent microsurgical resection and had a definite 31 pathologic diagnosis.

RESULTS

The age at diagnosis in the solid/cystic group was the highest among the 3 groups (P < 0.05). The solid/cystic group showed the shortest symptom duration (P < 0.05), which was related to obvious peritumoral brain edema (P < 0.05). The combination of computed tomography angiography and magnetic resonance imaging helped with the differential diagnosis. The solid/cystic group showed the lowest rate of gross total resection (P < 0.05) as a result of the obscure brain-tumor interface, and the guidance of intraoperative ultrasonography helped with the microsurgical procedures to a certain extent. Patients in the solid/cystic group showed greater intraoperative blood loss (P < 0.05), a lower ratio of symptom improvement (P < 0.05), and a longer mean hospital stay (P < 0.05) than did patients in the cystic group.

CONCLUSIONS

Cerebellar sporadic solid/cystic hemangioblastomas are rare and usually affect elderly people. The combination of computed tomography angiography and magnetic resonance imaging may improve the preoperative diagnosis. Solid/cystic hemangioblastomas showed the lowest rate of gross total resection as a result of the obscure brain-tumor interface.

Microsurgical Resection of an Intramedullary Ependymoma at the Cervicomedullary Junction: A Two-Dimensional Operative Video

Ependymomas are the most common adult intramedullary spinal tumors.¹ Although uncommon in the brainstem, ependymomas make up a large proportion of tumors of this location.^2-8 We present an operative video case report of an intrinsic ependymoma at the cervicomedullary junction. The purpose of this report is to present the clinical picture, operative setup, and surgical technique involved in resection of an intramedullary tumor of this region. For best outcome for intramedullary ependymomas, the goal should be gross total resection.^1,9,10 These tumors have a relatively distinct plane between tumor and normal parenchyma, making a gross total resection more probable than cases of infiltrative intramedullary astrocytomas.¹¹ Despite this, significant morbidity can be associated with treatment.¹ Proper microsurgical technique with use of operative adjuncts can maximize resection while minimizing neurologic injury to optimize outcomes in patients. We present the case of a 42-year-old man presenting with neck and shoulder pain, upper extremity paresthesias, and gait instability. Magnetic resonance imaging of the neuroaxis revealed a heterogeneously enhancing expansile lesion in the lower medulla and multiple lesions in the thecal sac, representing drop metastases. Due to symptoms and mass effect from the lesion, the patient underwent a suboccipital craniotomy for tumor resection. We highlight operative techniques in our case, including use of neurophysiologic monitoring, intraoperative ultrasound, ultrasonic aspirator, and dissection with microcottonoid pledgets and bimanual technique. Pathology revealed a World Health Organization grade II ependymoma. Postoperative magnetic resonance imaging revealed a small amount of residual. He underwent full craniospinal proton beam therapy with boost to the residual and metastases with good outcome. Patient provided consent for this report.

Hemangioblastomas of the Posterior Cranial Fossa in Adults: Demographics, Clinical, Morphologic, Pathologic, Surgical Features, and Outcomes. A Systematic Review

BACKGROUND

Posterior cranial fossa (PCF) hemangioblastomas are benign, highly vascularized, and well-differentiated tumors with well-described histopathologic features. Although relatively rare, this tumor is the most prevalent primary tumor of the cerebellum in adults.

OBJECTIVE

Because the demographics of patients with such a tumor (as well as the clinical, morphologic, pathologic, surgical features, and outcomes) are not fully understood, we systematized characteristic patient and tumor features.

METHODS

We undertook a systematic review of the English-language literature in PubMed for PCF hemangioblastomas in adults published in the past 31 years. We analyzed geographic distribution and year of publication of articles; demographic data of patients; presenting symptoms and clinical signs; tumor location and morphology; histopathologic features, extent of tumor resection, perioperative blood loss, and postoperative complications; length of hospital stay; and outcomes.

RESULTS

We reviewed 207 articles describing 1759 infratentorial hemangioblastomas in a cohort of 1515 adult patients. We found female predominance in patients with Von Hippel-Lindau disease (VHLD) compared with male predominance in the general patient group. Symptoms of intracranial hypertension were more common in the VHLD group compared with the general group of patients. The cerebellar location was more common in the VHLD group and solid (parenchymatous) tumor was the most common type. Most patients underwent total resection but rate of resection did not differ between the general and VHLD groups. Most patients had a favorable outcome.

CONCLUSIONS

The literature of adult PCF hemangioblastomas is limited and general surgical experience with such tumors is scarce because of their rarity. Rates of postoperative complications and mortality remain higher than expected. However, prognosis and surgical outcomes are generally favorable. Nevertheless, surgery of adult PCF hemangioblastomas is a demanding and challenging task.

Surgical resection of sporadic and hereditary hemangioblastoma: Our 10-year experience and a literature review

Background:

Hemangioblastomas (HBLs) are benign neoplasms that contribute to 1-2.5% of intracranial tumors and 7-12% of posterior fossa lesions in adult patients. HBLs either evolve hereditarily in association with von Hippel–Lindau disease (vHL) or, more prevalently, as solitary sporadic tumors. Only few authors have reported on the clinical presentation and the neurological outcome of HBL.

Methods:

We retrospectively analyzed the clinical, radiological, surgical, and histopathologic records of 24 consecutive patients (11 men, 13 women; mean age 51.3 years) with HBL of the posterior cranial fossa, who had been treated at our center between 2001 and 2012. We reviewed the current literature, and discussed our findings in the context of previous publications on HBL. The study protocol was approved by the local ethics committee (14-101-0070).

Results:

Mean time to diagnosis was 14 weeks. The extent of resection (EOR) was total in 20 and near total in 4 patients. Four patients required revision within 24 h because of relevant postoperative bleeding. One patient died within 14 days. One patient required permanent shunting. At discharge, 75% of patients [n = 18, modified Rankin scale (mRS) 0-1] showed no or at least resolved symptoms. Mean follow-up was 21 months. Two recurrences were detected during follow-up.

Conclusions:

In comparison to other benign entities of the posterior fossa, time to diagnosis was significantly shorter for HBL. This finding indicates the rather aggressive biological behavior of these excessively vascularized tumors. In our series, however, the rate of complete resection was high, and morbidity and mortality rates were within the reported range.

Clinico-radiological profile and nuances in the management of cervicomedullary junction intramedullary tumors

BACKGROUND

Cervicomedullary junction (CMJ) intramedullary tumors comprise of tumors that often pose a surgical challenge even in the present era. Though classified under brainstem glioma CMJ tumors are well amenable for surgical resection and have a good outcome. Various factors are involved in the outcome of these patients following surgery and a proper pre-operative assessment is often required to reduce the morbidity and mortality.

MATERIALS AND METHODS

Patients admitted in the Department of Neurosurgery with a diagnosis of CMJ intramedullary tumors from January 2001 to January 2010 were included in the study. Patients were analyzed retrospectively regarding their symptomatology, clinical findings, radiology and outcome after surgery. All patients underwent pre-operative magnetic resonance imaging (MRI) and post-operatively all were managed in the neurosurgery intensive care unit for days to weeks or as dictated by the clinical condition of the patient.

RESULTS

A total of 32 patients were included in the present study. The number of males was 21 (65.6%) and females were 11 (34.4%) respectively. The mean age of presentation was 22.97 ± 9.8 years and the mean duration of pre-operative symptoms was 13.3 ± 12.9 months. The tumor had extension from the CMJ into the cervical region in 17 (53.1%) and into the medullary region in 14 (43.8%) patients. Tumor decompression was done in 9 (28.1%) patients and gross near total excision done in 23 (71.87%) patients.

CONCLUSIONS

Cervicomedullary tumors are a subset of tumors quite distinct from the usual brainstem tumors. Patients having predominant cervical involvement present early and have less post-operative deficits. Those with predominantly more medullary involvement present late, hence have a much more morbid outcome. Though closely related to vital neural structures, surgery forms the mainstay of treatment. Adequate pre-operative planning and preparation of the patient along with intense post-operative monitoring and ventilatory assistance as and when required helps in a good surgical outcome.

Posterolateral sulcus approach for spinal intramedullary tumor of lateral location: technical note

Posterolateral sulcus (PLS) approach of the spinal cord, being equivalent to the dorsal root entry zone myelotomy, may offer the satisfactory exposure of the spinal intramedullary tumor if applied appropriately. Eight consecutive patients with spinal intramedullary tumors of lateral location underwent the surgery of PLS approach in our institute. There were 6 male and 2 female patients, ranging in age from 34 to 72 years (mean, 57 years). PLS approach was indicated for the intramedullary tumor situated laterally in the spinal cord and that do not contact the posterior or lateral surfaces on magnetic resonance (MR) images before surgery. Total removal of the tumor was achieved in 6 cases except of 2 cases of anaplastic astrocytoma. All 6 patients with total removal of the tumor demonstrated the modest or mild deterioration of motor function on the approach side early after surgery, which resolved within 1 month after surgery. Average grade of the modified McCormick functional schema was 3.5 before surgery and improved to 3.0 at 3 months after surgery. These 6 patients demonstrated satisfactory pain relief early after surgery. Average grade of the sensory pain scale was 2.7 before surgery and improved to 1.7 at 3 months after surgery. PLS approach can be one of the surgical choices to the spinal intramedullary tumors, if applied appropriately. Better indication for PLS approach may be the tumors of the uneven location within the spinal cord associated with moderate or severe local pain.

Intramedullary medullocervical ependymoma--surgical treatment, functional recovery, and long-term outcome

To evaluate the long-term outcome and functional recovery of intramedullary medullocervical ependymoma (IME), the clinical charts of 38 surgically treated consecutive cases of IME were reviewed. Follow-up was obtained prospectively. The mean age of the patients (19 male and 19 female) was 35.3 years (range: 11-60 years). Complete resection was achieved in 33 (86.8%) patients. Fourteen patients worsened postoperatively; five and seven of these improved to their baseline levels within 1 and 3 months, respectively. By 1 year postoperatively, 17 patients returned to work. After a mean follow-up duration of 81.5 months, 31 patients improved or stabilized, and 3 had recurrence. The means of the modified McCormick grade (mMG) scores before the operation, at discharge, 1 year after the operation, and at the most recent evaluation were 1.76, 2.13, 1.82, and 1.84, respectively. A favorable long-term outcome of the mMG was associated with a good preoperative status (mMG I) (odds ratio [OR] = 9.956, p = 0.008) and well-defined tumor boundary (OR = 7.829, p = 0.035). Improvements in the postoperative walking dysfunction and paresthesia over time were associated with the absence of preoperative walking dysfunction (p = 0.047) and paresthesia (p = 0.028), respectively. The 12-year progression/recurrence-free survival and overall survival rates were 92.0% and 93.7%, respectively. The study suggests that the goal of surgery is to stabilize the preoperative neurological function and that a favorable outcome may be achieved in patients with good preoperative statuses and well-defined tumor boundaries. Surgery should be performed as soon as possible after the diagnoses and before the neurological functions deteriorate.

Prognosis by tumor location in adults with spinal ependymomas

OBJECT

Ependymomas are primary central nervous system tumors that occur more frequently in the spines of adults than they do there in children. Previous studies consist mainly of retrospective single-institutional experiences or case studies. In this study, a comprehensive literature review was performed on reported cases of spinal ependymoma treated with resection to determine whether tumor location along the spinal axis conveys important prognostic information.

METHODS

A PubMed search was performed to identify all papers that included data on patients with spinal ependymoma. Only cases involving adult patients who underwent ependymoma resection with a clearly reported tumor location were included for analysis. Tumor locations were separated into 6 groups: cervicomedullary, cervical, cervicothoracic, thoracic, thoracolumbar, and conus + cauda equina. Kaplan-Meier survival and Cox regression analyses were performed to determine the effect of tumor location on progression-free survival (PFS) and overall survival (OS).

RESULTS

A total of 447 patients who underwent resection of spinal ependymomas with clearly indicated location of tumor were identified. The most common locations of spinal ependymomas were the cervical (32.0%) and conus + cauda equina (26.8%) regions. The thoracolumbar and cervicomedullary regions had the fewest tumors (accounting for, respectively, 5.1% and 3.4% of the total number of cases). The conus + cauda equina and thoracolumbar regions had the highest percentage of WHO Grade I tumors, while tumors located above these regions consisted of mostly WHO Grade II tumors. Despite the tendency for benign grades in the lower spinal regions, PFS for patients with spinal ependymomas in the lower 3 regions (thoracic, thoracolumbar, conus + cauda equina) was significantly shorter (p < 0.001) than for those with tumors in the upper regions (cervicomedullary, cervical, cervicothoracic), but the difference in OS did not achieve statistical significance (p = 0.131).

CONCLUSIONS

Spinal ependymomas along different regions of spinal axis have different characteristics and clinical behaviors. Tumor grade, extent of resection, and PFS varied by tumor location (upper vs lower spinal regions), while OS did not. Recurrence rates were higher for the lower spinal cord tumors, despite a greater prevalence of lower WHO grade lesions, compared with upper spinal cord tumors, suggesting that tumor location along the spinal axis is an important prognostic factor.

Adjuvant radiotherapy delays recurrence following subtotal resection of spinal cord ependymomas

BACKGROUND

Ependymoma is the most common glial tumor of the adult spinal cord. Current consensus recommends surgical resection with gross total resection (GTR) whenever possible. We performed a comprehensive review of the literature to evaluate whether adjuvant radiotherapy after subtotal resection (STR) has any benefit.

METHODS

A PubMed search was performed to identify adult patients with spinal cord ependymoma who underwent surgical resection. Only patients who had clearly defined extent of resection with or without adjuvant radiotherapy were included for analysis. Kaplan-Meier and multivariate Cox regression survival analyses were performed to determine the effects of adjuvant radiotherapy on progression-free survival (PFS) and overall survival (OS).

RESULTS

A total of 348 patients underwent surgical resection of spinal cord ependymomas, where GTR was obtained in 77.0% (268/348) of patients. Among those who received STR, 58.8% (47/80) received adjuvant radiotherapy. PFS was significantly prolonged among those who received adjuvant radiotherapy after STR (log rank; P < .001). This prolonged PFS with adjuvant radiotherapy remained significant in multivariate Cox regression analysis (STR versus STR + RT group; hazard ratio (HR) = 2.26, P = .047). By contrast, improved OS was only associated with GTR (GTR versus STR + RT group; HR = 0.07, P = .001) and benign ependymomas (HR = 0.16, P = .001).

CONCLUSIONS

Surgery remains the mainstay treatment for spinal cord ependymomas, where GTR provides optimal outcomes with longest PFS and OS. Adjuvant radiotherapy prolongs PFS after STR significantly, and OS is improved by GTR and benign tumor grade only.

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.

Diagnosis and surgical treatment of brainstem hemangioblastomas

OBJECTIVE

The study aims to elucidate the advance of diagnosis and surgical treatment of brainstem hemangioblastomas (BSHs).

METHODS

The data of the following patients treated in one institute were retrospectively analyzed: (1) patients with a single tumor on the brainstem which was verified by surgery and pathology; (2) patients without von Hippel-Lindau disease or multiple hemangioblastomas.

RESULTS

Thirty-three patients with BSHs were identified, accounting for 15.5% of all intracranial hemangioblastomas surgically treated from August 1989 to May 2002 in Huashan Hospital. There were 17 males and 16 females. The patients were aged from 16 to 65 years with an average age of 45 years. The clinical manifestations were nonspecific. Magnetic resonance imaging and digital subtraction angiography were the major diagnostic modalities. Tumors were located on oblongata (14), ponto-oblongata (9), pons (6), and cervicomedulla (4). Tumors were solid in 29 cases, cyst in 4 cases, and had a small size in 5 (< or =3 cm), large in 19 (3.1-4 cm), and giant in 9 (>4 cm). Extra-brainstem (EBS) type (including the fourth-ventricle hemangioblastomas) was seen in 25 cases, and intrabrainstem (IBS) type in 8 cases. Preoperative embolization was performed in 12 cases since 1996. Mild hypothermia with or without hypotension was done during the operation in 10 cases. Total tumor removal was achieved in 31 patients (94%), and incomplete removal in 2 cases. Two patients with EBS type and giant solid tumors died after operation. Follow-up study (range, 1-12 years; mean, 5 years) was available in 31 patients. Karnofsky performance scale scores were > or =80 in 25 patients (80.6%), 60 to 70 in 4 patients (12.9%), and 40 to 50 in 2 patients (6.5%).

CONCLUSION

Two types of BSHs can be identified. Patients with cystic IBS type could obtain excellent outcome after operations. Patients with giant or large solid BSHs remain a challenge to neurosurgeons. A combined strategy of preoperative embolization, mild hypothermia with or without hypotension, microsurgical technique, and intensive perioperative management are mandatory for removal of these kinds of tumors with acceptable morbidity and mortality.

Surgical management of brainstem hemangioblastomas in patients with von Hippel-Lindau disease

OBJECT

Hemangioblastomas of the brainstem constitute 5 to 10% of central nervous system (CNS) tumors in patients with von Hippel-Lindau (VHL) disease. At present, optimal management of brainstem hemangioblastomas associated with VHL disease is incompletely defined. In an attempt to clarify some of the uncertainty about the operative treatment of these lesions and its outcome, the authors reviewed all cases of VHL disease in which resection of brainstem hemangioblastomas was performed at the National Institutes of Health during a 10-year period.

METHODS

Twelve consecutive patients with VHL disease (six male and six female patients [mean age 31.7 +/- 9 years; range 15-46 years]) who underwent 13 operations to remove 17 brainstem hemangioblastomas were included in this study (mean follow-up period, 88.4 +/- 37.4 months; range 37-144 months). Serial examinations, hospital charts, magnetic resonance images, and operative records were reviewed. To evaluate clinical course, clinical grades were assigned to each patient before and after surgery. Preoperative neurological function was the best predictor of long-term outcome. In addition, patients who underwent CNS surgeries for hemangioblastomas were more likely to improve or to remain neurologically stable. Tumor or cyst size, the presence of a cyst, or the location of the tumor (intramedullary, extramedullary, or mixed; posterior medullary, obex, or lateral) did not affect outcome. No patient was neurologically worse after brainstem surgery. At long-term follow-up review (mean 88.4 months), only one patient had declined neurologically and this was due to the cumulative neurological effects caused by eight additional hemangioblastomas of the spinal cord and their surgical treatment.

CONCLUSIONS

Brainstem hemangioblastomas in patients with VHL disease can be removed safely; they generally should be resected when they become symptomatic or when the tumor has reached a size such that further growth will increase the risks associated with surgery, or in the presence of an enlarging cyst. Magnetic resonance imaging is usually sufficient for preoperative evaluation and presurgical embolization is unnecessary. The goal of surgery is complete resection of the lesion before the patient experiences a disabling neurological deficit.

Radical excision of intramedullary spinal cord tumors: surgical morbidity and long-term follow-up evaluation in 164 children and young adults

OBJECT

The majority of intramedullary spinal cord tumors (IMSCT) in children and young adults are low-grade gliomas. Radical resection of similar tumors in the cerebral hemisphere or cerebellum is usually curative; however, the conventional management for IMSCTs remains partial resection followed by radiotherapy because of the concern for surgical morbidity. Nevertheless, radical resection of IMSCTs without routine adjuvant treatment has been the rule at our institution since 1980. In an attempt to resolve this controversy, the long-term morbidity and survival in a large series of children have been retrospectively reviewed.

METHODS

The database records and current status of 164 patients 21 years of age and younger in whom an IMSCT was resected were reviewed. A gross-total resection (>95%) was achieved in 76.8% of the surgical procedures. Subtotal resections (80-95%) were performed in 20. 1%. The majority of patients (79.3%) had histologically low-grade lesions. There were no deaths due to surgery. When comparing the preoperative and 3-month postoperative functional grades, 60.4% stayed the same, 15.8% improved, and 23.8% deteriorated. Only 13 patients deteriorated by more than one functional grade. Patients with either no deficits or only mild deficits before surgery were rarely injured by the procedure, reinforcing the importance of early diagnosis and treatment. The major determinant of long-term patient survival was histological composition of the tumor. The 5-year progression-free survival rate was 78% for patients with low-grade gliomas and 30% for those with high-grade gliomas. Patients in whom an IMSCT was only partially resected (<80%) fared significantly worse.

CONCLUSIONS

The long-term survival and quality of life for patients with low-grade gliomas treated by radical resection alone is comparable or superior to minimal resection and radiotherapy. The optimum therapy for patients with high-grade gliomas is yet to be determined.

Experimental study of medullary trigeminal evoked potentials: development of a new method of intraoperative monitoring of the medulla oblongata

OBJECT

The goal of this study was to develop a new method of intraoperative monitoring of functions located in the lateral portion of the medulla oblongata. Based on the fact that the spinal trigeminal nucleus and tract are located in the lateral portion of the medulla oblongata, the authors intended to investigate the efficacy of trigeminal evoked potentials (TEPs) in intraoperative monitoring for assessing functions of the medulla oblongata.

METHODS

Trigeminal evoked potentials induced by electrical stimulation of the infraorbital nerve were recorded from the dorsolateral portion of the medulla oblongata (M-TEP) and the cerebral sensory cortex (C-TEP) in dogs. When the lateral one-sixth portion of the medulla was cut, the amplitude of the M-TEP decreased markedly, but the amplitude of the C-TEP and the somatosensory evoked potential (SSEP) did not decrease. When the lateral one-third portion of the medulla was cut, the amplitude of the SSEP decreased, but that of the C-TEP showed no change. When the medulla was retracted, the amplitude of the M-TEP was more sensitive than that of SSEP. Pathological examinations revealed that retraction force less than 10 g and a reduction in the amplitude of the M-TEP less than 50% were safe.

CONCLUSIONS

These results suggest that M-TEPs obtained from the dorsolateral portion of the medulla oblongata by electrical stimulation of the trigeminal nerve are clinically applicable as a new means of intraoperative monitoring of the functions of the medulla oblongata.

Intramedullary spinal cord tumors in children under the age of 3 years

Over a 13-year period extending from 1980 to 1993, 27 children less than 3 years of age underwent operation for removal of an intramedullary spinal cord tumor (IMSCT). The majority (18 of 27) of children had undergone surgery before being referred to New York University (NYU) Medical Center. The most common reasons for radiological investigation were pain (42%), motor regression (36%), gait abnormalities (27%), torticollis (27%), and progressive kyphoscoliosis (24%). Forty procedures were performed in 27 children. Nine children underwent two operations and two children underwent three procedures. A gross-total resection was achieved in 72% of the procedures. There was no surgical mortality. A comparison of the preoperative and 3-month postoperative functional grades for the first NYU procedure (NYU-1) yielded the following findings: 20 patients' conditions remained the same, five patients improved, and two patients deteriorated. The functional outcomes of a second operation (NYU-2) were similar. The majority of the children (24 of 27, 89%) had histologically determined low-grade lesions. There were 12 patients with low-grade astrocytomas (Grades I-III), eight with gangliogliomas, two with ganglioglioneurocytomas, one with a glioneurofibroma, and one child with a mixed astro/oligodendroglioma. Two children had anaplastic astrocytomas (Grades II-III) and one child had a glioblastoma multiforme. In a median follow-up review of 76 months, two patients died and two patients were lost to follow up. The 3- and 5-year progression-free survival (PFS) rates were 81.7% (standard error of the mean (SEM) 0.083) and 76.2% (SEM 0.094), respectively. Eight of 24 patients suffered a recurrence within a mean time of 45.4 +/- 28.9 months. All were treated with surgery (NYU-2). Lesions recurred in three of 12 children with low-grade astrocytomas, two of eight children with gangliogliomas, one child with an anaplastic astrocytoma, one child with a ganglioglioneurocytoma, and one child with a glioblastoma multiforme. At follow-up review, most of these children were doing well. Sixteen are in functional Grades I or II and 18 children attend a normal school system. The authors conclude that surgery for the removal of IMSCTs in children less than 3 years of age can be performed radically and safely. The postoperative functional performance is determined by the degree of the preoperative deficit. It is, therefore, of utmost importance to diagnose and treat these children as early as possible. Spinal cord tumors should be recognized as potentially excisable lesions on their initial presentation and when they recur. The optimum treatment for malignant lesions is still to be determined.

Spinal cord tumors in children: long-term results of combined surgical and radiation treatment

The authors report a series of 31 children under 17 years of age with primary spinal cord tumors who underwent radiation treatment following decompression laminectomy with or without tumor resection between 1959 and 1990. The tumors consisted of 15 astrocytomas, 11 ependymomas, one mixed glioma, one gangliolioma, and three of unknown histology. Ten- and 20-year survival rates and 10- and 20-year relapse-free survival rates for the 28 patients with known histology were 80% and 53%, and 73% and 67%, respectively. Eleven patients (35%) had no resection, 14 (45%) had a partial resection, and six (19%) had a grossly complete resection. Eight patients (26%) are dead: five due to recurrent tumor, two due to a second malignant tumor, and one due to intercurrent disease. primary tumor relapse or progression occurred in nine patients (29%), four of whom were salvaged. A second malignant tumor developed in four patients (13%), two of whom died. Local control of the tumor was finally achieved in 26 cases (84%), despite either grossly incomplete or no resection in 25 of these cases (81%). These statistics suggest that radiation treatment without resection may achieve long-term control in children with astrocytoma or ependymoma of the spinal cord.