Surgical Results for Meningiomas of the Craniocervical Junction

Madjid Samii, M.D., Jörg Klekamp, M.D., Gustavo Carvalho, M.D.

Medical School of Hannover, Neurosurgical Clinic, Nordstadt Hospital, Hannover, Germany

OBJECTIVE: We have undertaken a retrospective analysis of 38 patients who were operated on for 40 meningiomas of the craniocervical junction between September 1977 and August 1995 to determine which factors influenced resectability, complications, and postoperative outcomes.
METHODS: Radiological examinations, clinical data, and operation notes were evaluated, and additional follow-up information was obtained from outpatient examinations, telephone calls, and questionnaires.
RESULTS: Four groups could be distinguished according to dural attachment as follows: 1) 15 spinocranial meningiomas originated from the spinal canal and extended intracranially; 25 craniocervical meningiomas of intracranial origin were divided into 2) meningiomas of the lower clivus (10 patients with 11 tumors), 3) lateral meningiomas (11 patients with 12 tumors), and 4) posterior meningiomas (2 patients). Standard midline or lateral suboccipital approaches with opening of the foramen magnum and laminectomy of the involved cervical segments were sufficient for the great majority of tumors. In seven instances only, drilling the posterior third of an occipital condyle was needed. Twelve of 15 spinocranial meningiomas and 13 of 25 craniocervical meningiomas could be removed totally. One patient underwent ventriculoperitoneal shunting only. With a rate of 63% of totally removed and 30% of subtotally removed meningiomas in this region, we observed clinical recurrences for two patients only. Complications were encountered in 30% of patients, predominantly with recurrent and/or infiltrative or en plaque meningiomas. Whereas motor weakness and gait ataxia tended to improve postoperatively, cranial nerve deficits usually remained unaltered.
CONCLUSION: The relationship of the tumor to neighboring structures, i.e., the vertebral artery in particular, determines its resectability. We recommend using extreme caution with recurrent or en plaque meningiomas and tumors associated with extensive arachnoid scarring.
(Neurosurgery 39:1086­1095, 1996)

Key Words: Arachnoid scarring, Craniocervical junction, Meningioma

Meningiomas of the craniocervical junction may originate from the clivus, the cerebellopontine angle, or the occiput and extend into the spinal canal across the foramen magnum (craniocervical meningiomas) or may originate in the spinal canal and grow rostrally into the cranial cavity (spinocranial meningiomas) (3). Surgical removal poses several problems. The tumor may encase the vertebral, basilar, and their perforating arteries and cranial nerves, may invade bony structures of the craniocervical junction, or may be densely adherent to the brain stem. A variety of surgical approaches have been advocated to facilitate resection and limit postoperative morbidity. We present our experience with these challenging tumors over a period of 17 years and analyze which factors determine postoperative outcome, predispose to complications, and limit the resectability of meningiomas in this area.


During the period from October 1977 to August 1995, a total of 40 meningiomas of the craniocervical junction in 38 patients were treated surgically in the Department of Neurosurgery at the Nordstadt Hospital in Hannover, Germany. Case records, operation reports, follow-up data, and neuroradiological findings were evaluated. The clinical course was documented using the Karnofsky score (10) and a score system for each symptom (11) (Table 1). In general, scores between 3 and 5 describe satisfactory levels of function and scores between 2 and 0 indicate unsatisfactory or incapacitated function. Only the most severely affected limb or side of the body was analyzed in this manner. Preoperative imaging consisted of plain x-rays, computed tomographic (CT) scans (including bone windows), and magnetic resonance imaging (MRI) enhanced with gadolinium. Angiography was not performed routinely in these patients and was considered on an individual basis.

TABLE 1. Clinical Scoring System.
Score Sensory Deficits, Pain, Dysesthesias Motor Weakness Gait Ataxia Bladder Function Bowel Function Caudal Cranial Nerve Deficit
5 No symptom Full power Normal Normal Normal Normal
4 Present, not significant Movement against resistance Unsteady, no aid Slight disturbance, no catheter Slight disturbance, full control Present but no swallowing problem
3 Significant, funtion not restricted Movement against gravity Mobile with aid Residual, no catheter Laxatives, full control Mild disturbance, fluid intake possible
2 Some restriction of function Movement without gravity Few steps with aid Sometimes catheter Sometimes loss of control Severe disturbance, aspiration with fluid intake
1 Severe restriction of function Contraction without movement Standing with aid Often catheter Often loss of control Severe disturbance, oral food intake impossible
0 Incapacitation of function Plegia Wheel chair Permanent catheter No control Swallowing not possible

Meningiomas of the craniocervical junction were defined according to their tumor matrix, i.e., origin of the tumor or dura insertion. All tumors in this study arose between the level of the lower third of the clivus and C2 (5). According to their origin, four types could be characterized as follows (Table 2): 1) spinocranial (tumor matrix below level of foramen magnum and tumor mass ventral or lateral to brain stem and spinal cord) (Fig. 1), 2) craniospinal (tumor matrix intracranially), clivus (tumor matrix localized at the lower clivus and tumor mass ventral to brain stem and spinal cord) (Fig. 2), 3) craniospinal, lateral (tumor matrix localized in the cerebellopontine angle or the dura opening for the verterbral artery and tumor mass predominantly lateral to brain stem and spinal cord) (Fig. 3), 4) craniospinal, posterior (tumor matrix localized in the region of the cisterna magna and tumor mass dorsally to cerebellum and spinal cord) (Fig. 4).

TABLE 2. Localization of Meningiomas of the Craniocervical Junction.
Type Craniospinal Spinocranial
Posterior Lateral Clivus
With capsule 2 5 9 14
En plaque 0 7 2 1
Total 2 12 11 15

FIGURE 1. Gadolinium-enhanced MRI scans of a spinocranial meningioma in a 22-year-old woman with neurofibromatosis Type 2 and gait ataxia, sensory deficits on the left side, and sphincter dysfunction. The tumor was removed via a lateral suboccipital approach combined with a laminectomy of C1 and C2. The patient made a complete recovery and was without recurrence 15 months postoperatively.

FIGURE 2. Gadolinium-enhanced MRI scans of a clivus meningioma in a 46-year-old patient with occipital pain without neurological deficits. Vertebral or basilar arteries were not involved (A, B). The postoperative CT scan with bone window after 1 week shows the amount of drilling of the right occipital condyle that was required for complete resection via a lateral suboccipital approach and hemilaminectomy C1 (C). The tumor matix was cauterized. One year postoperatively, the patient was without recurrence or neurological deficit.

FIGURE 3. Gadolinium-enhanced MRI scans and CT scan with bone window of an extensive lateral calcified meningioma of the craniocervical junction extending between the cerebellopontine angle and C2 with encasement of the right vertebral artery and displacement of brain stem left vertebral , and basilar arteries in a 24-year-old woman with occipital pain, slight gait ataxia, and deficits of Cranial Nerves V, VIII, IX, and X (A­C). The postoperative CT scan obtained after 1 week demonstrates the extent of bony removal required for complete resection. Condyles were not resected (D, E). The dural attachment was located at the dural entry of the right vertebral artery and was cauterized. Postoperatively, pain, gait ataxia, and Cranial Nerves V, IX, and X recovered. The gadolinium-enhanced postoperative MRI scan obtained after 1 year (F) shows a recurrent tumor around the right vertebral artery. The patient complained about occipital pain again and underwent a subsequent operation via the same approach. A complete resection was achieved once more. One year postoperatively, the patient was without recurrence and had slight residual deficits of Cranial Nerves VIII, IX,and X.

FIGURE 4. Gadolinium-enhanced MRI scan and CT scan with bone window of a posterior calcified meningioma of the craniocervical junction in a 40-year-old bedridden patient with severe tetraparesis and occipital pain (A, B). The tumor was removed completely, including dural resection from a midline suboccipital approach with laminectomy of C1 and C2. C, gadolinium-enhanced MRI scan obtained 2 months postoperatively. The patient made a gradual recovery. Five months postoperatively, the patient regained walking ability and is still undergoing rehabilitative therapy.

Whereas the major tumor mass was situated intracranially in craniocervical meningiomas, it was found in the spinal canal of spinocerebral meningiomas (3). Additionally, encapsulated and en plaque growing tumors could be distinguished according to intraoperative findings. En plaque meningiomas were characterized by extensive dura infiltration, absence of a tumor capsule, and violation of tissue planes.

The approach consisted of a laminectomy or hemilaminectomy of the upper cervical spine, depending on the extent of the meningioma, and a craniectomy with opening of the foramen magnum either in the midline (midline approach) or toward the sigmoid sinus as a lateral suboccipital approach (lateral approach) in the semisitting position. The positioning, as well as the remainder of the operation, was performed under monitoring of somatosensory evoked potentials (SEPs). Depending on the localization of the tumor, the posterior third of an occipital condyle or facet joints were resected to gain a more lateral access. After dural opening, the arachnoid was inspected for evidence of scarring. Arachnoid dissection was performed only as required for safe removal of the meningioma. Care was taken to preserve the arachnoidal plane between tumor and surrounding nervous structures. In general, the meningioma was debulked first before dissection along these arachnoidal planes was performed to mobilize the tumor from vessels, cranial nerves, or brain stem. Whenever possible, the tumor matrix was excised with the tumor. If this was considered too difficult or hazardous, the matrix was cauterized with bipolar forceps. In cases with an infiltrative or en plaque growth pattern, no attempt was made to remove the tumor radically unless it was clearly separable from neighboring vessels or cranial nerves.

Total removal was defined as complete resection of the tumor mass with resection or cauterization of the tumor matrix. Subtotal resection was defined as resection of the tumor mass with small tumor remnants left behind at important structures, such as the vertebral artery, perforating arteries, or cranial nerves. Partial resection was defined as incomplete resection of the tumor mass.

Postoperatively, every patient underwent computed tomography and, since the advent of MRI, gadolinium-enhanced MRI after 3 and 12 months. Further scans were obtained if new clinical symptoms evolved or if tumor removal had been incomplete. Clinical examinations were performed before discharge and after 3 months for all patients. Additional follow-up information was obtained by further outpatient examinations, regular telephone calls, or questionnaires.

A recurrence was defined clinically as neurological deterioration after surgical treatment, independent of evidence for recurrent tumor growth on CT or MRI scans. Surgical morbidity was defined as a new postoperative neurological deficit or an aggravation of a preexisting symptom without subsequent recovery.

Means are presented plus or minus the standard deviation. For statistical analyses, Student\'s t tests for paired or unpaired variables were used, provideed the Komolgorov-Smirnov tes indicated normal data distribution. A multiple regression analysis was performed to determine which factors were of significant importance for the resectability of a particular tumor, the probability of recurrence, and postoperative outcome. A difference was considered significant if a P value of 0.05 was reached.


Patient data

During the period from October 1977 to August 1995, 38 patients were operated on for 40 meningiomas of the craniocervical junction. The average age of the patients was 49 ± 16 years (range, 17­74 yr). Female sex predominated by a factor of 2:1 (25 female and 13 male patients). The average history until admission for surgery was 28 ± 37 months. We observed a tendency for a shorter history in patients with craniocervical meningiomas compared to those with spinocerebral meningiomas (22 ± 22 and 38 ± 51 mo, respectively; not significant). The majority of patients demonstrated a slowly progressive course. One patient presented with a history of 14 years. Neurofibromatosis Type 2 was present in five patients.

Neck pain or headache (31%), gait ataxia (23%), and motor weakness (21%) were generally reported as the first symptom. The remaining patients complained about cranial nerve deficits (13%), dysesthesias (8%), or sensory changes (3%) at the beginning.

At admission, the major concerns were gait ataxia (28%), cranial nerve deficits (23%), and pain (21%). Motor weakness (15%), sensory changes (5%), and dysesthesias (5%) were mentioned less often as the main complaint. Craniocervical meningiomas were more likely to present with cranial nerve deficits than were spinocerebral meningiomas, whereas the reverse relationship was observed for pain, dysesthesias, and sensory deficits. Four patients presented with obstructive hydrocephalus. A more detailed overview on preoperative neurological symptoms is provided in Table 3. We did not observe differences in presentation for patients with encapsulated (n = 29) or infiltrative meningiomas (n = 10). The average Karnofsky score at presentation was 66 ± 19, indicating significant preoperative neurological deficits for the majority of patients.

TABLE 3. Preoperative Clinical Symptoms of Patients with Meningiomas of the Craniocervical Junction
Craniospinal Spinocranial
Sensory deficit 10 (40%) 11 (73%)
Dysesthesias 3 (12%) 5 (33%)
Pain or headache 12 (48%) 11 (73%)
Motor weakness 13 (52td> 10 (67%)
Gait ataxia 17 (68%) 11 (73%)
Sphincter disturbance 5 (20%) 4 (27%)
Cranial nerve deficits
XII 10 (40%) 2 (13%)
IX and X 11 (44%) 3 (20%)
XI 7 (28%) 3 (20%)
VII 2 (8%) 0
VIII 7 (28%) 1 (7%)
V 7 (28%) 2 (13%)
Hydrocephalus 4 (16%) 0

Localization and extension of meningiomas

According to localization of the tumor matrix and extension of the meningioma, 25 craniocervical meningiomas (clivus, lateral, or posterior) and 15 spinocerebral meningiomas could be distinguished (Table 2). Two tumors demonstrated bony infiltration. Eleven patients were operated on for recurrent meningiomas (two spinocerebral, six lateral, and three clivus meningiomas).

Approaches and surgical findings

Thirteen of 15 spinocerebral meningomas were operated on via a midline approach and 2 via a lateral approach. For one spinocerebral meningioma, drilling the posterior third of an occipital condyle was necessary to remove the tumor (Table 4).

TABLE 4. Type of Approach for Meningiomas of the Craniocervical Junctiona
Type of Meningioma Midline Approach Dorsolateral Approach Ventriculoperitoneal Shunt
Spinocranial 13 2 (1) 0
Clivus 1 9 (4) 1
Lateral 0 12 (2) 0
Posterior 2 0 0

aNumbers in bracket = number of patients who underwent drilling of the posterior third of the occipital condyle.

All except three craniocervical meningiomas were removed using a lateral approach. One patient in bad general health with a recurrent clivus meningioma underwent ventriculoperitoneal shunting for accompanying hydrocephalus only. For exposure of 2 of 12 lateral and 4 of 10 clivus meningiomas, partial resection of an occipital condyle was required (Figs. 2 and 3). In one patient, a clivus meningioma was misdiagnosed, using CT scans before MRI was available, as a tumor of the fourth ventricle, and it was attacked via a midline approach. After partial removal, clinical symptoms caused by tumor growth developed after 8 years and a complete resection was performed via a lateral suboccipital approach (Table 5). Both posterior meningiomas were removed using a midline approach (Table 4).

TABLE 5. Type of Operation for Meningiomas of the Craniocervical Junction
Complete Removal Subtotal Removal Partial Removal Ventriculoperitoneal Shunt
Spinocranial 12 (80%) 3 (20%) 0 0
Craniospinal 13 (52%) 9 (36%) 2 (8%) 1 (4%)
Clivus 6 (55%) 3 (27%) 1 (9%) 1 (9%)
Lateral 5 (42%) 6 (50%) 1 (8%) 0
Posterior 2 (100%) 0 0 0
With capsule 26 (90%) 3 (10%) 0
En plaque 0 8 (80%) 2 (20%)
First operation 20 (69%) 8 (28%) 1 (3%) 0
Recurrent tumor 5 (45%) 4 (36%) 1 (9%) 1 (9%)
Vertebral artery encased 5 (31%) 9 (56%) 2 (13%)
Vertebral artery not encased 20 (87%) 3 (13%) 0

Displacement of the vertebral artery was observed in seven instances and encasement in 16 (Fig. 3). Displacement and encasement of the basilar artery was found in two patients. Extensive arachnoid scarring around the tumor was found in 15 patients (5 patients at first surgery and all 10 patients with recurrent tumors).

Surgical results

Complete tumor removal was achieved for 63% and subtotal removal for 30% of all patients. The tumor matrix was resected and a duraplasty performed in 17 patients. For the remaining patients, the inner dural layer was removed and/or the matrix cauterized. For two patients (5%), tumor removal was partial. A multiple regression analysis revealed that intracranial origin of the meningioma, infiltrative or en plaque growth, and encasement of the vertebral artery were independent predictors of incomplete tumor removal (P < 0.01) (Table 5).

Complications occurred in 30% of patients (Table 6). Postoperative tracheostomy was required in four patients, and prolonged feeding via a gastric tube was required in three patients. One patient required a gastrostomy. The most severe complication was aspiration caused by postoperative lower cranial nerve dysfunction affecting four patients. Two of these developed pneumonia and died, indicating a surgical mortality of 6%. Transient worsening of caudal cranial nerve function was observed in four patients, and another four patients with lateral meningiomas acquired transient facial palsies. Six patients demonstrated a temporary aggravation of their gait ataxia postoperatively. A multiple regression analysis revealed that recurrent tumor, arachnoid scarring, craniocervical type, and no preoperative lower cranial nerve deficit were independent predictors of postoperative aspiration (P < 0.01, respectively).

TABLE 6. Complications
Type of Complication With Capsule En Plaque
Infection 1 0
Aseptic meningitis 0 1
Postoperative hydrocephalus 1 0
Postoperative pneumocephalus 0 1
Loss of SEPsa 0 1
Gastrointestinal hemorrhage 0 1
Aspiratin pneumonia 1 3
Postoperative permanent deficit 1 1
Total 12 (30%) 4 (14%) 8 (80%)

aSEP, somatosensory evoked potential.

Two patients acquired a permanent postoperative deficit (surgical morbidity 5%). One 67-year-old patient with a lateral en plaque growing meningioma, which was exposed from a lateral suboccipital approach and found to be very adherent to medulla, cranial nerves, and the vertebral artery, acquired lower cranial nerve deficits that did not recover. An 18-year-old patient with neurofibromatosis Type 2 was operated on for a lateral craniocervical meningioma via a lateral suboccipital approach. No difficulties were encountered during surgery, with complete resection of the encapsulated tumor. Postoperatively, the patient demonstrated an incomplete paraparesis with a spinal level at L1. A spinal tumor or a compressive lesion in the area of operation was ruled out by myelography. The patient made an incomplete recovery.

Patients were followed for an average period of 21 ± 33 months (maximum, 10 yr). We observed two recurrences for a partially removed meningioma after 8 years and a completely removed meningioma after 11 months (Fig. 3). Both patients were operated on again, and a complete and a subtotal removal were achieved, respectively. Currently, both patients are free of recurrence.

In general, patients benefited significantly from surgery. Although the majority of preoperative cranial nerve deficits tended to remain unchanged postoperatively, sensory changes (t test for paired variables, P = 0.042), dysesthesias (t test for paired variables, P = 0.0134), pain (t test for paired variables, P = 0.0061), and gait ataxia (t test for paired variables, P = 0.0111) improved during the 1st postoperative year. The average Karnofsky score increased from 63 ± 17 to 73 ± 12 (t test for paired variables, not significant), indicating that the majority of patients were able to live independent lives postoperatively (Table 7).

TABLE 7. Postoperative Course for Patients with Meningiomas of the Craniocervical Junction
Patient Group No. Preoperatively At Discharge Postoperatively
3 Months 6 Months 1 Year
Sensory deficits 14 3.6 ± 1.1 3.9 ± 0.9 4.1 ± 0.9 4.2 ± 0.8 4.3 ± 0.7a
Dysesthesias 14 4.1 ± 1.3 4.4 ± 0.9 4.7 ± 0.6 4.8 ± 0.4 4.8 ± 0.4a
Pain 14 3.5 ± 1.3 3.9 ± 0.9 4.2 ± 0.7 4.2 ± 0.7 4.2 ± 0.7b
Motor weakness 14 3.7 ± 1.0 3.9 ± 0.6 4.4 ± 0.5 4.4 ± 0.9 4.4 ± 0.9c
Gait ataxia 13 3.5 ± 1.1 3.5 ± 1.1 4.1 ± 1.2 4.2 ± 0.9 4.2 ± 1.0a
Sphincter function 13 4.5 ± 1.1 4.5 ± 0.9 4.8 ± 0.6 4.8 ± 0.4 4.8 ± 0.4c
Accessory nerve 13 4.8 ± 0.6 4.0 ± 1.9 4.1 ± 1.9 4.1 ± 1.9 4.1 ± 1.9b
Cranial nerves IX and X 13 4.4 ± 1.0 4.2 ± 1.6 4.5 ± 0.9 4.5 ± 0.8 4.6 ± 0.8c
Hypoglossal nerve 13 4.6 ± 0.8 4.2 ± 1.5 4.2 ± 1.5 4.2 ± 1.5 4.2 ± 1.5c
Facial nerve 13 4.9 ± 0.3 4.6 ± 0.8 4.7 ± 0.7 4.8 ± 0.6 4.8 ± 0.6a
Karnofsky score 14 63 ± 17 64 ± 16 70 ± 15 73 ± 11 73 ± 12c

aSignificant difference between preoperative and 1-year postoperative scores (t test for paired variables, P < 0.05).
bSignificant difference between preoperative and 1-year postoperative scores (t test for paired variables, P < 0.01).
cDifference not significant.


We have documented surgical results for 40 meningiomas of the craniocervical junction in 38 patients treated during the period from October 1977 to August 1995. The preoperative clinical course was slowly progressive, leading to gait ataxia for the majority of spinocerebral meningiomas and to cranial nerve dysfunction for craniocervical meningiomas (5, 7, 12, 17, 22, 24, 27). This difference in clinical presentation not only reflects the localization of the major tumor mass but also indicates that cranial nerves tend to be compromised by meningiomas of intracranial origin before signs of brain stem compression develop.

Surgical approach

Depending on localization of the tumor matrix and tumor extension, the meningioma was approached through a midline occipital craniectomy with laminectomy of the required upper cervical vertebrae or through a standard lateral suboccipital craniectomy extended to the foramen magnum combined with a hemilaminectomy. Drilling the occipital condyle was not required to provide appropriate exposure of the tumor in most cases and was performed in seven instances only.

Meningiomas are known for their delicate relationship to neighboring structures. In the region of the foramen magnum, this poses particular problems with meningiomas, which originate anteriorly to the brain stem or demonstrate significant anterior extension, as several vital structures may be involved. A number of surgical approaches have been used in the past to expose and completely remove such tumors. A transoral approach has been used for these meningiomas (2, 18). However, a number of disadvantages apply with this technique. The surgical field may be contaminated and is limited laterally (16). Meningiomas encasing the vertebral artery or extending laterally toward the dura entry of the vertebral artery cannot be managed appropriately. None of the five meningiomas described in these publications were removed completely. Complications include postoperative cerebrospinal fluid leak, craniocervical instability, and velopalatine insufficiency (2, 18). Alternatively, a transcervical, retropharyngeal approach has been described (7, 13, 15, 21, 25, 26). However, this approach has been applied mainly for extra dural lesions. The surgical field is deep and is limited rostrally and laterally by the internal carotid artery (13, 16, 26).

Because of these limitations of anterior or anterolateral approaches, lateral approaches are most widely used to remove meningiomas anterior or lateral to the brain stem. The general principle of bony resection to gain free exposure of the area and to limit manipulations of nervous structures has led several surgeons to recommend the so-called far lateral or extreme lateral approach for meningiomas of the craniocervical junction (1, 12, 20, 23). The anatomic structures limiting the surgeon laterally are the occipital condyle, the jugular bulb, the sigmoid sinus, and the vertebral artery. Basically, the far lateral or extreme lateral approach is a variant of the lateral suboccipital approach with opening of the foramen magnum, as described in this article. The characteristic feature refers to the extent of the drilling of the occipital condyle to enable mobilization of the vertebral artery at its dural entry, both medially and laterally. However, analyzing axial CT scans with bone windows reveals that the angle of approach and the working space for the surgeon are sufficient once a standard lateral suboccipital craniotomy is combined with drilling the posterior third of the occipital condyle (1, 9, 12, 16, 19) (Fig. 2). Therefore, we consider terms such as extreme lateral, far lateral, or transcondylar for this kind of approach to be misleading.

Surgical results

In this series, complete tumor removal was achieved in 63% of patients and subtotal removal in 30% of patients. For 5% of patients, partial tumor removal was performed. One patient received a ventriculoperitoneal shunt. Several series reported results obtained by similarly designed, modified suboccipital approaches. George et al. (5) reported on a series of 106 craniocervical meningiomas from 21 hospitals. Seventy-seven percent were removed completely, 16% subtotally, and 7% partially. In general, the rate of complete tumor removal was higher with the lateral compared to the midline approach. Yasargil et al. (27) reported on 23 meningiomas of the craniocervical junction. Ten were removed completely, whereas 13 subtotal removals were performed using a lateral suboccipital approach in 7, a subtemporal approach in 8, a frontolateral-subtemporal approach in 4, and a posterior midline approach in 3 instances.

Kratimenos and Crockard (12) operated on 15 ventrally located craniocervical tumors with varying histologies via a far lateral approach. They achieved 12 complete resections and 3 subtotal removals, with seven of eight meningiomas removed completely. With a similar technique, Bertalanffy and Seeger (1) reported five virtually complete resections of six tumors in this region. Sen and Sekhar (20) removed three of five craniocervical meningiomas by an extreme lateral approach. Even though the data presented by these authors suggest a higher rate of complete resections with the far lateral transcondylar approach, the numbers of patients described are limited. They do not provide conclusive evidence that the more extended approach was the decisive factor to enable complete removal.

According to our analysis, craniocervical meningiomas (3), infiltrative or en plaque growing meningiomas (27), and meningiomas with encasement of the vertebral artery (7, 27) were more likely to be resected incompletely. George et al. (5) found encasement of the vertebral artery, anterior tumor localization, and extra dural extension to be associated with a lower rate of complete resections. Similarly, Guidetti and Spallone (7), Hakuba et al. (8), and Stein et al. (24) described encasement of the vertebral artery as a limiting factor for removal of craniocervical meningiomas. The relationship between tumor and surrounding structures, i.e., the presence or absence of an arachnoidal sheath, is the crucial point that determines the extent of removal (4, 27) and postoperative morbidity. It was our policy throughout not to risk serious neurological deficits by aggressive removal of tumor parts densely adherent to or infiltrating important vessels or nerves. A more aggressive strategy for these patients would have led to higher rates of permanent surgical morbidity and mortality. Furthermore, even a complete removal, as judged by the surgeon intraoperatively, does not exclude the possibility of a recurrence.


Complications occurred in 30% of patients (Table 6) and transient new postoperative neurological symptoms after 14 operations. Aspiration was observed in four patients, which led to fatal aspiration pneumonia in two. A 57-year-old patient with an infiltrating lateral meningioma was operated on for the second recurrence of this tumor via a lateral suboccipital approach. He had no preoperative deficit of the lower cranial nerves and presented with a moderate right tetraparesis. The tumor was removed subtotally. Postoperatively, the patient demonstrated an accentuated tetraparesis and was reintubated because of dysfunction of lower cranial nerves and aspiration pneumonia. He eventually died 3 weeks later as a result of respiratory failure.

A 60-year-old patient with a recurrent en plaque growing lateral meningioma demonstrated moderate dysfunction of the lower cranial nerves and a tetraparesis preoperatively. The tumor was partially removed via a lateral suboccipital approach. Postoperatively, she made a slow recovery and reported slight improvement of her swallowing function and tetraparesis. Ten days postoperatively, the patient showed signs of a left-sided pneumonia. Klebsiella and Pseudomonas could be isolated. Despite adequate antibiotic therapy, the patient died 3 weeks postoperatively with signs of adult respiratory distress syndrome. We consider aspiration the most likely cause of the pneumonia.

According to our multiple regression analysis, patients operated on for recurrent meningiomas, those with arachnoid scarring or intracranial dura attachment, and those without preoperative lower cranial nerve deficits were at high risk for postoperative aspiration pneumonia. Dissection of arachnoid scars around cranial nerves should be avoided to limit the risk of postoperative lower cranial nerve dysfunctions. We emphasize the importance of the preoperative status of the lower cranial nerves. A patient with preoperative dysfunction of lower cranial nerves is accustomed to this problem and at lower risk for postoperative aspiration than a patient without preoperative experience of swallowing difficulties. Moreover, in patients with preoperative swallowing dysfunction, this problem has developed slowly and compensatory mechanisms could be developed easier, compared to a sudden postoperative deficit of lower cranial nerve function. For all patients with craniocervical tumors, we now examine lower cranial nerve function postoperatively during extubation with the aid of a bronchoscope. If swallowing function is markedly impaired and the vocal cords are paralyzed, we reintubate the patient and proceed with tracheostomy, as performed for one patient after removal of an extensive meningioma. Using this policy, no further aspiration pneumonias occurred in this group.

Kratimenos and Crockard (12) reported on two deaths in their series of eight craniocervical meningiomas that resulted from aspiration pneumonia and its consequences. Other studies provide mortality rates of 3.5% (28), 5% (17), 9% (27), and 11% (7), which indicates a marked improvement compared to older studies with mortality rates of 19% (29) or 45% (14).

Two additional patients acquired neurological deficits with surgery. Although the follow-up period is short for both patients and although some recovery may still occur, the deficits were considered permanent for this report. One patient demonstrated new lower cranial nerve deficits and required a tracheostomy and prolonged gastric tube feeding to prevent aspiration pneumonia. The most likely cause for the incomplete paraparesis after surgery in the semisitting position for the other, 18-year-old patient seems to be a vascular type injury to the spinal cord. Similar morbidity rates were reported in the literature (5, 6, 12, 27).

As for other pathological abnormalities of the foramen magnum, we emphasize the importance of monitoring SEPs not only during surgery but also during positioning of the patient. For one patient, SEPs deteriorated during positioning without recovery after the position was changed. Anaesthesia was terminated and the patient allowed to recover. Fortunately, no neurological deficit had developed, and SEPs recovered subsequently. Under SEP monitoring the patient was positioned again a few days later. The tumor could be removed completely and no neurological problems appeared postoperatively.

During surgery, deterioration of SEPs prompted the surgeon, on a number of occasions, to either interrupt further dissection to allow for recovery of evoked potentials or to change the operative strategy in terms of debulking instead of mobilization of the tumor or to dissect a different part of the tumor. If SEPs recovered intraoperatively, no permanent neurological deficits developed postoperatively.

Clinical results

In general, surgery led to a favorable outcome, even if the tumor could not be resected completely. With a follow-up of up to 10 years, we observed two recurrences after 11 months and 8 years, respectively. Similar reports in the literature suggest a benign natural history for these meningiomas (5, 27). If postoperative MRI scans demonstrate a recurrent meningioma or a tumor remnant, we postpone surgery until neurological signs start to develop. As long as the neurological situation is stable, we follow the patient closely with repeated physical and MRI examinations. If the postoperative MRI scan after 1 year does not demonstrate any tumor, we do not perform further scans routinely, because we would not recommend surgery on a recurrent tumor without accompanying symptoms. We recognize that because of this policy, we may underestimate the rate of radiological recurrences.

The majority of preoperative cranial nerve deficits remained unchanged postoperatively. On the other hand, signs and symptoms for upper cervical cord or medullary compression tended to improve with surgery. This difference in postoperative outcome may be explained by several mechanisms. Cranial nerves are more vulnerable structures, compared to the upper cervical cord or the medulla. They may be compromised by the tumor itself because of compression or encasement or because of dissection for tumor removal. However, recovery of function for a significant number of patients would have to be expected if compression or postoperative swelling of a cranial nerve was the main reason for dysfunction. We consider compromise of small perforating arteries arising from the vertebral artery by the meningioma to be an important factor. Ischemic lesions of cranial nerve nuclei will also lead to cranial nerve dysfunction and carry a worse prognosis in terms of postoperative recovery. This might explain why the majority of cranial nerve deficits do not recover after otherwise successful surgery. Nevertheless, the average postoperative Karnofsky score after 12 months increased to 73 ± 11, which indicates that most patients were living independent lives (5) and benefited significantly from surgery.


With progressive neurological symptoms, complete tumor removal should be attempted. We found standard approaches, such as a lateral suboccipital or midline occipital approach combined with appropriate laminectomies or hemilaminectomies, to be sufficient for tumor removal in most instances. For ventrally placed tumors, drilling the posterior third of the occipital condyle provides sufficient additional access.

Localization of the tumor matrix, growth pattern of the meningioma, and involvement of the vertebral artery have a significant influence on the resectability of craniocervical meningiomas. To limit postoperative morbidity and mortality, we recommend using extreme caution with recurrent meningiomas and meningiomas accompanied by arachnoid scarring.

Received, November 21, 1995.
Accepted, July 8, 1996.
Reprint requests: Jörg Klekamp, M.D., Medical School of Hannover, Neurosurgical Clinic, Nordstadt Hospital, Haltenhoffstr. 41, 30167 Hannover, Germany.


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The authors present a retrospective review of 38 patients who underwent surgical resection for meningiomas of the craniocervical junction between 1977 and 1995 (40 tumors). The symptomatology has been reviewed as well as the surgical pathological classification and a careful review of the postoperative results. This is a significant series of 15 spinocranial and 25 craniospinal tumors diagnosed using computed tomography and, subsequently, magnetic resonance imaging. The authors correctly point out that the majority of spinocranial tumors can be resected (13 gross resections of 15 tumors), whereas only half of the craniospinal lesions could be totally removed at the time of initial operation (13 of 25 tumors). Encasement of the vertebrobasilar system was found in 18 of 40 tumors.

The complication rate of 30% reported is mainly seen with the en plaque craniospinal lesions, those that cross tissue planes, and recurrent tumors. These also were the predictors of an incomplete resection.

I strongly agree with the statement that preoperative existing hypoglossal and glossopharyngeal nerve deficits do not recover postoperatively, but, paradoxically, these patients do not develop aspiration. In contradistinction, newly acquired postoperative lower cranial nerve deficits have the attendant morbidity of aspiration and swallowing dysfunction. These need to be kept in mind in the immediate postoperative period (2, 3). The increasing tendency to perform "transcondylar, far lateral" approaches to the craniovertebral junction have their actual roots in the posterolateral approach with partial resection of the posterior third of the occipital condyle. This has been well recognized and demonstrated (1) in this article. I, however, have not found somatosensory evoked potential monitoring to be of value in these cases.

Arnold H. Menezes
Iowa City, Iowa

  1. Menezes AH: Surgical approaches to the craniocervical junction, in Frymoyer J (ed): The Adult Spine: Principles and Practice. New York, Raven Press, 1991, pp 967­985.
  2. Menezes AH, Traynelis VC: Tumors of the craniovertebral junction, in Youmans JR (ed): Neurological Surgery. Philadelphia, W.B. Saunders Co., 1995, ed 4, pp 3041­3072.
  3. Menezes AH, Traynelis VC, Gantz BJ: Surgical approaches to the craniovertebral junction. Clin Neurosurg 41:187­203, 1994.

Meningiomas of the craniocervical junction present a surgical challenge because of involvement of the adjacent brain stem, vertebral artery, and lower cranial nerves. Samii et al. provide a candid and comprehensive analysis of their experience with these tumors, with particular emphasis on the difficulties associated with location, en plaque tumors, and arachnoid scarring. In our experience, the development of cranial base techniques, such as the far lateral approach, have been important in reducing brain stem and cranial nerve injuries while facilitating more extensive tumor removal. As the authors demonstrate, however, it is not always necessary to perform a more extensive cranial base approach when a simpler approach may be sufficient. It is also important to note the benign history of incompletely resected tumors, because it may be desirable to leave tumor behind rather than risk morbidity from aggressive tumor resection.

Jeffrey N. Bruce
Bennett M. Stein

New York, New York

Samii et al. relate their valuable experience in this large series of meningiomas of the craniocervical junction. I share their concern over two points, and they cannot be overemphasized.

One is the high morbidity of lower cranial nerve deficits, the intense postoperative care they warrant, and the requirement of aggressive use of tracheostomy for airway protection and management of secretions. We also frequently and very early in the course proceed with a vocal cord medialization that provides significant improvement in the function of lower cranial nerves. I also emphasize how crucial the dissection within an arachnoid membrane is and the importance of the presence of intervening arachnoid membrane to the safe removal of these lesions.

I do, however, respectfully defer to the authors in regard to the need and the effectiveness of condyle drilling. Although a posteriorly or laterally positioned meningioma might not require extensive drilling of the condyle, a truly ventral meningioma that is located medially to the vertebral artery will require extensive drilling of the condyle. Condyle drilling should be tailored to each case, but in all cases, it contributes greatly to the ease and safety of the meningioma removal.

I also think that radical removal of these meningiomas needs to be attempted with zeal at initial operation; as the authors have shown, that is the best time to achieve a cure. Our experience indicates that many of the encased vertebral arteries are separable because of intervening arachnoid membrane. Although the authors had one patient on whom they operated for a regrowth of residual tumor, their average length of follow-up is relatively short and the availability of radiological follow-up in their study will not permit the conclusion of a benign natural history and low recurrence rate.

Ossama Al-Mefty
Little Rock, Arkansas

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