[Toxicity of pesticides used in chrysanthemum crops to eggs and nymphs of Orius insidiosus (Say) (Hemiptera: Anthocoridae)]

The objective of this study was to evaluate the toxicity of some pesticides used in chrysanthemum crops to eggs and nymphs of Orius insidiosus (Say). The bioassays were carried out at 25 +/- 2 degrees C, 70 +/- 10% RH and 12h photophase. For the tests with eggs, stems of Bidens pilosa L. previously exposed to predator oviposition were dipped for five seconds in aqueous dilution of the pesticides, using 40 eggs per treatment. The pesticides were applied on nymphs using a Potter's tower. Forty first-instar and twenty second-instar nymphs of O. insidiosus were used per treatment in the tests with nymphs. The adults from eggs and nymphs treated were grouped in couples to study the pesticides effects on its reproductive parameters. None tested pesticide affected the viability of treated eggs. Azoxystrobin, benomyl, imibenconazole, iprodione, metalaxyl + mancozeb and triforine were harmless to first- and second-instar nymphs of O. insidiosus, whereas abamectin, acephate and chlorfenapyr were shown to be harmful to nymphs of both first and second instars. The pre-oviposition period, the daily number of eggs, number of eggs in ten days, and egg viability were not affected by azoxystrobin, benomyl, imibenconazole, iprodione, metalaxyl + mancozeb and triforine. These pesticides, for showing low toxicity to the predator, can be recommended in disease management programs for chrysanthemum crops, in association with O. insidiosus.

Surgical management of brainstem cavernomas

OBJECT

A careful retrospective analysis of 36 cases was performed to evaluate the pre- and postoperative rates of morbidity that occur in patients with brainstem cavernous angiomas.

METHODS

The authors evaluated immediate postoperative and follow-up outcomes with regard to clinical findings, the incidence of preoperative hemorrhage(s), location and size of the lesions, and the timing of the surgical procedure after the last hemorrhagic event. Specifically. the following parameters were analyzed: 1) number of hemorrhages; 2) the precise brainstem location (pontomesencephalic, pons, and medulla oblongata); 3) pre- and postoperative cranial nerve status; 4) pre- and postoperative motor and sensory deficits; 5) size (volume) of the lesions; and 6) pre- and postoperative Karnofsky Performance Scale (KPS) scores. Multiple hemorrhages were observed in 16 patients, particularly in those with pontomesencephalic cavernous angiomas (75%). The mean preoperative KPS score was 70.3 +/- 16.3 (+/- standard deviation). Twenty-six patients (72.2%) presented with cranial nerve impairment, 13 (36.1%) with motor deficits, and 17 (47.2%) with sensory disturbance. Volume of the lesions ranged from 0.18 to 18.18 cm3 (mean 4.75 cm3). Postoperative complications included new cranial nerve deficits in 17 patients, motor deficits in three, and new sensory disturbances in 12 patients. In a mean follow-up period of 21.5 months, KPS scores were 80 to 100 in 22 patients. Timing of surgery (posthemorrhage) and multiple hemorrhages did not influence the long-term results. Higher preoperative KPS scores and smaller-volume lesions, however, were factors associated with a better final outcome (p < 0.05). Major morbidity was related mainly to preoperative status and less to surgical treatment. The incidence of new postoperative cranial nerve deficits was clearly lower than that demonstrated preoperatively because of the brainstem hemorrhages.

CONCLUSIONS

Based on these findings, resection of brainstem cavernomas is the treatment of choice in the majority of these cases because of the high incidence of morbidity related to one or often several brainstem hemorrhages.

Subthalamic nucleus lesions are neuroprotective against terminal 6-OHDA-induced striatal lesions and restore postural balancing reactions

Inactivation of the subthalamic nucleus (STN) by deep brain stimulation or lesioning can ameliorate symptoms in Parkinson' disease (PD) and may alter the underlying progressive degenerative process. We evaluated the effects of STN lesions in a terminal lesion model of PD in rats. Multiple intrastriatal 6-OHDA injections (4 x 7 microg) resulted in a partial loss of striatal TH-positive innervation (-30 to -40%) and nigral dopaminergic neurons (-60%), which was associated with behavioral deficits as observed in drug-induced rotational asymmetry, side-stepping, and postural balancing reactions. Unilateral ibotenic acid lesions of the STN did produce a 50-60% loss of STN neurons based on stereological analysis, which did not induce a functional impairment in rotational asymmetry or spontaneous sensorimotor behaviors. When STN lesions were performed 1 week prior to the 6-OHDA terminal striatal lesions, a significant rescue effect (+23%) on nigral dopaminergic neurons against terminal 6-OHDA neurotoxicity could be demonstrated, whereas striatal TH-positive fiber loss was not attenuated in these animals. In addition, animals with combined STN and striatal lesions exhibited a significant recovery in postural balancing reactions induced by 6-OHDA terminal lesions and did not show a significant impairment in any of the other behavioral parameters examined. Taken together, STN lesions can exert neuroprotective effects on nigral dopamine neurons in a partial lesion model of PD which result in recovery of spontaneous sensorimotor behavior. These findings may therefore provide new insights into the functional interaction between the glutamatergic and the dopaminergic neurotransmitter systems and foster novel therapeutic concepts for the early and middle phases of Parkinson's disease.

Intracerebral epidermoid tumor: a case report and review of the literature

BACKGROUND

Intracerebral epidermoid cysts are rare lesions and may account for only 1.5% of intracranial epidermoid tumors. Cell entrapment from the mesectodermal origin of the neural crest within the primitive cerebral hemisphere may lead to the formation of such rare intracerebral lesions.

METHODS

An intracerebral epidermoid cyst located in the right temporal lobe that was surgically treated is presented. The origin, clinical course, radiological features, and surgical treatment of such uncommon lesions are discussed based on a review of the literature.

RESULTS

Intraoperative findings revealed an epidermoid tumor. The postoperative course was uneventful and the patient was discharged with no neurological deficits. On long-term follow-up (2 years), there were no signs of recurrence.

CONCLUSIONS

Truly intracerebral epidermoid tumors are rarely found. Cells originating from mesectodermal lines may migrate and remain trapped within the primitive cerebral hemisphere while the neural tube is closing, leading to the formation of such intraparenchymal epidermoid tumors. Accurate preoperative diagnosis can be very difficult due to the radiological similarities to other common intracerebral cysts (e.g., astrocytomas or gliomas). Magnetic resonance imaging (MRI) studies, especially with diffusion-weighted images, allow greater accuracy in the preoperative differential diagnosis. Radical surgical removal should be attempted, but a less aggressive surgical strategy should be considered if there is strong adherence between the tumor capsule and the brain tissue, particularly in eloquent areas.

Neurenteric cyst of the craniocervical junction. Report of three cases

Neurenteric cysts of the craniocervical junction (CCJ) are very rare lesions. Their origin is the subject of long-standing controversy, but a failure during the embryogenic phase may be responsible for their formation. Accurate histopathological diagnosis may be difficult due to the similarity they share with other cystic lesions such as colloidal cysts, Rathke cysts, and cystic teratomas. Surgical removal is the treatment of choice for intracranial neurenteric cysts, but in some cases, infiltration of the surrounding structures may hinder complete resection. Three cases of neurenteric cysts located at the CCJ are reported.

Impact of computed tomographic and magnetic resonance imaging findings on surgical outcome in petroclival meningiomas

OBJECTIVE

The preoperative radiological findings of computed tomographic and magnetic resonance imaging scans of 70 patients with petroclival meningioma were evaluated and statistically compared with the degree of surgical resection and patients' outcomes to depict the most important radiological findings that may influence surgical radicality and outcome.

METHODS

The following parameters were evaluated: 1) tumor diameters; 2) tumor extension toward the middle fossa, the internal auditory canal, the brainstem, and the foramen magnum; 3) bone changes; 4) peritumoral edema; 5) signs of tumor infiltrative pattern; and 6) surgical radicality. Postoperative results were analyzed immediately after the surgery and in a long-term follow-up study.

RESULTS

Larger tumors affected a younger population and presented a significantly shorter time until symptom onset. In the majority of cases (67%), the tumor extended to the parasellar region. Tumor extension toward the jugular foramen was found in 24% of the patients and reached the level of the foramen magnum in 18%. Irregular tumor margins were found in 67% of the tumors, and 50% of them presented peritumoral edema in addition. Interestingly, edema also was found in 20% of tumors with well-delineated margins.

CONCLUSION

Tumor size, brainstem compression, and tumor extension laterally to the internal auditory canal did not influence either the degree of surgical resection or the long-term outcome (P > 0.05). Supratentorial tumor extension to the middle fossa and downward involving the caudal cranial nerves displayed a significant importance in regard to the surgical radicality and the patient's outcome, respectively (P < 0.05). Radiological evidence of infiltrative tumor pattern and peritumoral edema at the brainstem surface were important parameters regarding surgical radicality (P < 0.05). However, only peritumoral edema influenced the long-term results significantly.

Search for abnormalities of nuclear corepressors, coactivators, and a coregulator in families with resistance to thyroid hormone without mutations in thyroid hormone receptor beta or alpha genes

The syndrome of resistance to thyroid hormone (RTH) is characterized by decreased tissue responsiveness to thyroid hormones. Inheritance is usually autosomal dominant due to mutations in the ligand-binding domain or adjacent hinge region of the thyroid hormone receptor beta (TRbeta) gene. Six of 65 families with the RTH phenotype studied in our laboratory had normal TRbeta1 and TRbeta2 gene sequences. Their clinical characteristics were not different from those of subjects with TRbeta gene mutations. Four of the 6 families were amenable to linkage analysis, and TRalpha involvement was excluded. Candidate genes were then evaluated for their possible involvement in the RTH phenotype in these 4 families: 2 coactivators [NCoA-1 (SRC-1) and NCoA-3 (AIB-1)], 2 corepressors (NCoR and SMRT), and a coregulator (RXRgamma). DNA was obtained from 8 affected subjects and 41 of 45 living first degree relatives. In 2 of the 4 families, the mode of inheritance could be determined by pedigree analysis and was found to be autosomal dominant. Linkage analyses were performed using polymorphic markers near or within the 5 candidate genes. When analyses were not informative or linkage could not be excluded, direct sequencing of the genes in question was performed. Involvement of NCoA-1 was excluded in all four families assuming autosomal dominant inheritance. Roles for NCoR, SMRT, and NCoA-3 were excluded in three and a role for RXRgamma was excluded in two of the four families. However, if the two families without proven dominant mode of inheritance were compound heterozygous, only the involvement of NCoA-1 could be excluded in both. Roles for NCoR, SMRT, and RXRgamma were excluded in one of these two families. Thus, NCoA-1 and RXRgamma genes were not found to be the cause of RTH in subjects without TR gene mutations even though the absence of NCoA-1 and RXRgamma is the cause of RTH in mice. Involvement of other candidate genes in the mediation of thyroid hormone action as well as intracellular hormone transport needs to be explored in these families with non-TRbeta, TRalpha RTH.

Subarachnoid fat dissemination after resection of a cerebellopontine angle dysontogenic cyst: case report and review of the literature

OBJECTIVE AND IMPORTANCE

This case report illustrates the clinical and radiological relevance of extensive intracranial subarachnoid and ventricular dissemination in dysontogenic (dermoid) tumors.

CLINICAL PRESENTATION

We describe a patient with a cerebellopontine angle dysontogenic tumor. Postoperatively, the cyst disseminated fat particles extensively into the subarachnoid space. Magnetic resonance imaging (MRI) studies revealed continuous dispersion of the fat particles into the cerebral cisterns, subarachnoid space, and ventricles.

INTERVENTION

Eight years of clinical and MRI follow-up demonstrated neither neurological deterioration in the patient nor growth of the multiple lesions.

CONCLUSION

Intracranial subarachnoid dissemination of fat material may occur during the preoperative or postoperative course of dermoid and epidermoid cysts. Aseptic meningitis or other complications such as hydrocephalus, seizures, or cranial nerve deficits also may occur owing to spillage of intracranial cyst contents into the subarachnoid space. MRI can detect the presence of fat drops that may adhere to the surrounding structures or migrate with the cerebrospinal fluid flow. Intracranial disseminated fat particles can remain silent without radiological or neurological change, justifying a wait-and-see approach. During long-term postoperative follow-up, however, regular MRI studies and clinical examinations are necessary to avoid potential complications.

Cystic schwannomas of the jugular foramen: clinical and surgical remarks

OBJECTIVE

The goals of this report were to outline the clinical presentation, radiological characteristics, surgical techniques, postoperative morbidity, and long-term follow-up results for cystic jugular foramen (JF) schwannomas and to describe their differences, compared with solid schwannomas involving the JF.

METHODS

A retrospective analysis of radiological studies and surgical records identified five primarily cystic tumors among 21 cases of JF schwannomas that had been surgically treated at our institution.

RESULTS

Two types of cystic JF schwannomas were observed, i.e., Type 1 lesions, which are single large cysts with thin ring-like enhancement of the tumor wall, and Type 2 lesions, which are multiple cysts with very irregular, thick enhancement of the cyst wall. The most common symptoms were hearing loss, ataxia, and headaches. Total surgical removal could be performed in all cases. The immediate postoperative findings indicated hearing improvement in three cases. No deterioration of lower cranial nerve function was observed. All patients were independent in the immediate postoperative period and in the long-term follow-up period (Karnofsky Performance Scale score, 90).

CONCLUSION

Surgical treatment of cystic JF schwannomas can be very demanding because of generally stronger adhesion of the tumor capsule to the surrounding structures, fragile tumor capsules, and difficulty in identification of the arachnoidal planes in some cases. Early identification of the arachnoidal planes without opening of the cyst and sharp dissection may be useful. Careful intradural opening of the JF should be performed to achieve total removal of the last tumor portion within the JF. A comparison of these lesions with solid schwannomas involving the JF indicated that cystic tumors affected a younger population, with less preoperative swallowing impairment (P < 0.05). The immediate postoperative course in both types of cystic JF schwannomas was usually better than for solid lesions, because of minor postoperative cranial nerve morbidity, especially involving lower cranial nerve function, in the latter cases. Long-term follow-up data failed to demonstrate any significant differences in final patient outcomes, however.

Retrosigmoid intradural suprameatal approach to Meckel's cave and the middle fossa: surgical technique and outcome

OBJECT

The goal of this study was to determine whether some petroclival tumors can be safely and efficiently treated using a modified retrosigmoid petrosal approach that is called the retrosigmoid intradural suprameatal approach (RISA).

METHODS

The RISA was introduced in 1983, and since that time 12 patients harboring petroclival meningiomas have been treated using this technique. The RISA includes a retrosigmoid craniotomy and drilling of the suprameatus petrous bone, which is located above and anterior to the internal auditory meatus, thus providing access to Meckel's cave and the middle fossa. Radical tumor resection (Simpson Grade I or II) was achieved in nine (75%) of the 12 patients. Two patients underwent subtotal resection (Simpson Grade III). and one patient underwent complete resection of tumor at the posterior fossa with subtotal resection at the middle fossa. There were no deaths or severe complications in this series; all patients did well postoperatively, being independent at the time of their last follow-up examinations (mean 5.6 years). Neurological deficits included facial paresis in one patient and worsening of hearing in two patients.

CONCLUSIONS

The approach described here is a useful modification of the retrosigmoid approach, which allows resection of large petroclival tumors without the need for supratentorial craniotomies. Although technically meticulous, this approach is not time-consuming; it is safe and can produce good results. This is the first report on the use of this approach for petroclival meningiomas.

Arachnoid cysts of the posterior fossa

BACKGROUND

The surgical indications and management of posterior fossa arachnoid cysts (AC) are still controversial. Different surgical techniques and management have already been suggested for arachnoid cysts of the posterior fossa. AC involving the posterior fossa and especially the cerebellopontine angle may carry a high surgical morbidity because of the involvement of important neurovascular structures (e.g., brain stem and cranial nerves). Only long-term follow-up will determine the best surgical technique for such lesions.

METHODS

Between 1990 and 1996 a total of 12 patients underwent surgery for arachnoid cysts involving the posterior fossa. In seven cases AC were located within the cerebellopontine angle (CPA), in three cases in the CPA with major extension dorsal to the brainstem, and in two cases at the CPA extending into the internal auditory canal.

RESULTS

A suboccipital retrosigmoid approach was performed in all patients. Radical resection of the cyst could be accomplished in all but one case. There was no mortality. Major postoperative morbidity was present in one case because of an intraoperative air embolism in the semisitting position and strong adherence of the cyst wall to the surrounding neurovascular structures. Long-term follow-up (mean, 3.3 years) revealed improvement of most preoperative symptoms.

CONCLUSION

Open surgery and radical removal of the AC located at the posterior fossa, based on our retrospective analysis, provide very good long-term postoperative results. The suboccipital approach provides a good and safe exposure of vascular structures and cranial nerves in the CPA and allows radical resection of the cyst, reducing the chance of recurrence.

Diagnosis and surgery of brachial plexus injuries

The surgical outcome of traumatic injuries of the brachial plexus (BP) depends on the following parameters: 1) accurate preoperative diagnosis of cervical root avulsion; 2) time interval between injury and surgery; 3) delicate handling of the nerve tissue; and 4) postoperative physiologic training. This report is based on a 15-year experience in brachial plexus surgery and is supported on the grounds of two major studies. In a prospective study, the authors controlled for the reliability of preoperative radiologic diagnosis by myelo-CT and MRI scans for 40 patients, to evaluate the integrity of the intraspinal cervical roots after brachial plexus injury. Surgical inspection via a cervical hemilaminectomy proved the accuracy of 85 percent and 52 percent of CT myelography and MRI, respectively. Retrospective statistical analyses were carried out of the long-term surgical results of 54 patients with traumatic injuries of the BP who received a grafting procedure between cervical roots C5 or C6 and the musculocutaneous nerve. Patients operated on up to 6 months after trauma showed a better result than patients operated on later than 12 months after trauma (p<0.05). In contrast, grafting between cervical root C5 or C6 and the use of different sural-graft sizes to reconstruct the musculocutaneous nerve demonstrated no statistically significant difference in the final outcome.

Microvascular decompression for superior oblique myokymia: first experience. Case report

Superior oblique myokymia (SOM) is a rare eye movement disorder presenting as uniocular rotatory microtremor due to intermittent contractions of the superior oblique muscle. Medical treatment usually fails to provide long-term benefit for the patient and has considerable side effects. Surgical alternatives including tenotomy or partial tenectomy of the superior oblique tendon often result in incomplete resolution of the visual symptoms. The authors report a patient who experienced immediate cessation of disabling SOM following microvascular decompression of the fourth nerve at the root exit zone. Temporary double vision at downgaze resolved 5 months after surgery. There was no recurrence of oscillopsia during a follow-up of 22 months to date. From this single observation it appears likely that vascular compression of the trochlear nerve could be a significant pathophysiological factor contributing to SOM. In the hands of an experienced surgeon, microvascular decompression at the brainstem exit zone of this nerve may evolve as the method of choice for selected cases of disabling SOM.

Complete thyroxine-binding globulin (TBG) deficiency produced by a mutation in acceptor splice site causing frameshift and early termination of translation (TBG-Kankakee)

Fourteen T4-binding globulin (TBG) variants have been identified at the gene level. They are all located in the coding region of the gene and 6 produce complete deficiency of TBG (TBG-CD). We now describe the first mutation in a noncoding region producing TBG-CD. The proband was treated for over 20 yr with L-T4 because of fatigue associated with a low concentration of serum total T4. Fifteen family members were studied showing low total T4 inherited as an X chromosome-linked trait, and affected males had undetectable TBG in serum. Sequencing of the entire coding region and promoter of the TBG gene revealed no abnormality. However, an A to G transition was found in the acceptor splice junction of intron II that produced a new HaeIII restriction site cosegregating with the TBG-CD phenotype. Sequencing exon 1 to exon 3 of TBG complementary DNA reverse transcribed from messenger RNA of skin fibroblasts from an affected male, confirmed a shift in the ag acceptor splice site. This results in the insertion of a G in exon 2 and causes a frameshift and a premature stop at codon 195. This early termination of translation predicts a truncated TBG lacking 201 amino acids.

Complete deficiency of thyroxine-binding globulin (TBG-CD Buffalo) caused by a new nonsense mutation in the thyroxine-binding globulin gene

Complete deficiency of thyroxine-binding globulin (TBG-CD) is defined as undetectable TBG in the serum of affected hemizygous subjects. Four distinct mutations have been identified in the TBG gene that cause this phenotype: TBG-CDJ (Japan), TBG-CD6, TBG-CD5, and TBG-CD Yonago. We report a new mutation producing TBG-CD phenotype. Five family members were studied, including two affected males with undetectable TBG in serum and two obligatory heterozygote females with borderline low values. Sequencing of the exons encoding the mature protein, adjacent introns and the promoter region, revealed differences in two nucleotides compared to the common type TBG, both located in exon 3: TGG (Trp) TAG (Stop) at codon 280 and TTG (Leu) TTT (Phe) at codon 283. The former mutation was not previously described and the latter is a polymorphic variant. Genotyping revealed that the two affected males had the mutant and polymorphic allele and their obligatory heterozygous mothers have each a common type and a mutant allele associated with the polymorphic variant. The mutant TBG Trp280Stop causes premature termination of translation that results in the production of a truncated protein that lacks 116 carboxyl terminal amino acids. The latter is believed to be responsible for the TBG-CD either because the aberrant protein is not secreted or because of reduced abundance of its mRNA.

Surgical reconstruction of the musculocutaneous nerve in traumatic brachial plexus injuries

Over the last 16 years, 345 surgical reconstructions of the brachial plexus were performed using nerve grafting or neurotization techniques in the Neurosurgical Department at the Nordstadt Hospital, Hannover, Germany. Sixty-five patients underwent graft placement between the C-5 and C-6 root and the musculocutaneous nerve to restore the flexion of the arm. A retrospective study was conducted, including statistical evaluation of the following pre- and intraoperative parameters in 54 patients: 1) time interval between injury and surgery; 2) choice of the donor nerve (C-5 or C-6 root); and 3) length of the grafts used for repairs between the C-5 or C-6 root and the musculocutaneous nerve. The postoperative follow-up interval ranged from 9 months to 14.6 years, with a mean +/- standard deviation of 4.4 +/- 3 years. Reinnervation of the biceps muscle was found in 61% of the patients. Comparison of the different preoperative time intervals (1-6 months, 7-12 months, and > 12 months) showed a significantly better outcome in those patients with a preoperative delay of less than 7 months (p < 0.05). Reinnervation of the musculocutaneous nerve was demonstrated in 76% of the patients who underwent surgery within the first 6 months postinjury, in 60% of the patients with a delay of between 6 and 12 months, and in only 25% of the patients who underwent surgery after 12 months. Comparison of the final outcome according to the root (C-5 or C-6) that was used for grafting the musculocutaneous nerve showed no statistical difference. Furthermore, statistical analysis (regression test) of the length of the grafts between the donor (C-5 or C-6 root) nerve and the musculocutaneous nerve displayed an inverse relationship between the graft length and the postoperative outcome. Together, these results provide additional information to enhance the functional outcome of brachial plexus surgery.

Surgical management of meningiomas originating in Meckel's cave

OBJECTIVE

To define the difference of meningiomas that originate in the area of Meckel's cave (MC) (primary MC meningiomas) in regard to the different surgical approaches and postoperative results.

METHODS

A retrospective analysis of all meningiomas involving the cranial base displayed 21 cases of meningiomas originating in MC (primary MC meningiomas). These cases were classified according to the tumor extension in four different types: Type I, tumors mainly confined to MC; Type II, MC meningiomas with extension into the middle fossa; Type III, MC meningiomas with extension into the posterior fossa; and Type IV, MC meningiomas with extension into both middle and posterior fossae.

RESULTS

Trigeminal neuralgia resolved in all cases in this series, despite tumor type. Trigeminal hypesthesia showed postoperative improvement only in Type III MC meningiomas. In Types I and III, total removal without further morbidity was frequently achieved. Cavernous sinus infiltration, especially in Types II and IV, limited (in some cases) the extent of tumor extirpation.

CONCLUSION

Types I, II, and III MC meningiomas have a good prognosis. In most cases, very good outcomes are achieved. Radical tumor removal can usually be achieved without further morbidity and with postoperative improvement of the preexisting symptoms, especially in Types I and III MC meningiomas. On the contrary, Type IV MC meningiomas are usually only subtotally resected. Surgery in such cases may carry a high risk of additional morbidity, especially with regard to the IIIrd, IVth, and VIth cranial nerves. The postoperative outcome regarding facial pain in cases of all tumor types is usually very good. Trigeminal hypesthesia may persist after tumor removal in the majority of cases.

[Nerve transplantation and neurolysis of the brachial plexus after post-traumatic lesions]

Autologous transplantation in brachial plexus injuries has become significantly more efficacious through increased knowledge of the microtopographic anatomy of the fascicle structures and the refinement of microneurosurgical techniques. Recovery of shoulder and upper arm functions can be achieved with autologous transplantation in the majority of patients under optimized conditions. However, attempts to restore forearm, hand and finger functions in this way have been disappointing so far. Therapeutic success is primarily governed by early decision making, selection of adequate surgical strategies and intensive and longlasting postoperative management.

[Nerve transfer (neurotization) for functional reconstruction of arm functions in cervical root avulsions]

Neurotization procedures represent an important therapeutic option in patients with complete root avulsion due to traumatic brachial plexus injuries. A variety of normal donor nerves can be used, including intercostal nerves, accessory nerve, parts of the cervical plexus, phrenic nerve, and/or the contralateral C7 nerve root. The reconstructive neurotization procedure should be performed within 3-6 months following the trauma and, when successful, can lead to substantial improvement in motor function for the shoulder and upper arm and in sensory function for the forearm, hand and finger region. Neurotization can also be combined with neurolysis and/or transplantation to restore upper limb motor and sensory function in order to achieve greater therapeutic benefit for patients with posttraumatic brachial plexus lesions.

[Pain management after post-traumatic brachial plexus lesions. Conservative and surgical therapy possibilities]

The occurrence of sever pain is one of the most disabling symptoms after the traumatic lesion of the brachial plexus. Avulsion of one or more cervical roots of the brachial plexus is the main cause of severe pain, known as deafferentation pain. Lesion of the dorsal horn of the cervical spinal cord due to root avulsion may lead to important pathological changes and scarring that are responsible for the induction of pain sensations. Different medical and surgical treatment modalities have been established to relief such pain after brachial plexus injury. In contrast to drug therapy, which usually offers only limited benefit, surgical treatment over the last years has shown positive results. Coagulation of the dorsal root entry zone (DREZ) is one of the most efficient surgical treatments for these patients. Understanding of the pathophysiological changes and different pain mechanisms induced by traumatic injury of the brachial plexus is fundamental for the planning and step-wise treatment of such patients.

[Diagnosis and surgical indications of traumatic brachial plexus lesions from the neurosurgery viewpoint]

The precise preoperative clinical and electrophysiological evaluation of the brachial plexus as well as an exact radiological evaluation are the keystones for the treatment of traumatic injuries of the brachial plexus. Furthermore, surgical management and prognosis of traction injuries of the brachial plexus depend on the accurate diagnosis of root avulsion from the spinal cord. Myelography, myelo-computed tomography and recently magnetic resonance imaging are the main radiological methods for preoperative diagnose of cervical root avulsions. Surgical experience shows that in may cases, extraspinal findings diverge from intradural findings. Consequently, only correlation with the intradural surgical findings will allow us to define the factual accuracy of myelo-CT and MRI studies. Accuracy of the preoperative myelo-CT based diagnosis related to the intraoperative intradural findings was 85% On the other hand, MRI showed an accuracy of only 52%. Therefore, myelo-CT scans with 1 to 3 mm axial slices proves to be the most reliable method to evaluate preoperatively the presence of complete or partial root avulsion in traumatic brachial plexus injuries. However in 15% of the cases preoperative exact radiological diagnosis is unfortunately not reliable. In these special cases intraspinal surgical exposure of the cervical roots will provide the accurate diagnosis of root avulsion. Accurate clinical evaluation and exact assessment of intraspinal root avulsion simplify enormously the decision concerning the choice of donor nerves for transplantation and/or neurotization during brachial plexus surgery.

Cystic meningiomas resembling glial tumors

BACKGROUND

Meningiomas can be associated with peripheral or intratumoral cysts. Meningiomas with intratumoral cysts, also called "true cystic" meningiomas, are rare and can frequently be confused with glial or metastatic tumors.

METHODS

We report three cases of "true cystic" meningiomas and discuss the preoperative evaluation, etiology, and surgical treatment of these cystic lesions with reference to the literature.

RESULTS

Magnetic resonance imaging (MRI) and computed tomography (CT) studies usually display a cystic lesion close to the dura with or without enhancement of the cyst wall. Multiplanar MRI scans are very useful to show the presence of a solid tumor or some dural enhancement. Some cases of "true cystic" meningiomas however, are still erroneously preoperatively diagnosed. Complete surgical removal of the tumors and of the entire cyst wall was performed in our cases. Despite the absence of a typical ring enhancement of the cystic lesion in two cases, histopathologic studies displayed the presence of tumor cells on the cyst wall of both cases.

CONCLUSIONS

Tumor cells can be present on the cyst wall and therefore can be one of the causes of tumor recurrence if not totally removed. Accurate preoperative radiologic diagnosis (multiplanar MR images) and intraoperative histopathologic studies are fundamental in that they will definitely influence the surgical strategy and outcome.

Diagnosis of root avulsions in traumatic brachial plexus injuries: value of computerized tomography myelography and magnetic resonance imaging

Surgical management and prognosis of traction injuries of the brachial plexus depend on the accurate diagnosis of root avulsion from the spinal cord. Myelography, computerized tomography (CT) myelography, and recently magnetic resonance (MR) imaging have become the main radiological methods for preoperative diagnosis of cervical root avulsions. Most of the previous studies on the accuracy of CT myelography and MR imaging studies have correlated the radiological findings with the extraspinal surgical findings at brachial plexus surgery. Surgical experience shows that in many cases extraspinal findings diverge from intradural determinations. Consequently, only correlation with the intradural surgical findings will allow assessment of the factual accuracy of CT myelography and MR imaging studies. In a prospective study, 135 cervical roots (C5-8) were evaluated by CT myelography and/or MR imaging and further explored intradurally via a hemilaminectomy. The accuracy of the preoperative CT myelography-based diagnosis in relation to the intraoperative findings was 85%. On the other hand, MR imaging demonstrated an accuracy of only 52%. The most common reasons for false-positive or false-negative findings were: 1) partial rootlet avulsion; 2) intradural fibrosis; and 3) dural cystic lesions. Computerized tomography myelography scans using 1- to 3-mm axial slices prove to be the most reliable method to evaluate preoperatively the presence of complete or partial root avulsion in traumatic brachial plexus injuries. Because extradural judgment of cervical root avulsion can be unreliable, accurate assessment of intraspinal root avulsion enormously simplifies the decision concerning the choice of donor nerves for transplantation and/or neurotization during brachial plexus surgery.

Meningiomas of the tentorial notch: surgical anatomy and management

Twenty-five meningiomas located at the tentorial notch were surgically treated between 1978 and 1993 at the Neurosurgical Department of Nordstadt Hospital in Hannover, Germany. Nineteen meningiomas were classified as originating from the lateral tentorial incisura (Group I) and six were from the posteromedial tentorial incisura (Group II). Clinically, the most common symptom was trigeminal neuralgia, followed by headache. Neuroradiologically, 64% of the meningiomas were larger than 30 X 30 mm. Further evaluation revealed signs of brainstem compression in 88% of the patients. Radical surgical removal (Simpson I and II) was achieved in 88% of the cases. There was no mortality. Follow up revealed that 80% of patients were able to return to their premorbid activity. Surgical approaches to the tentorial notch included the suboccipital retrosigmoidal or the combined subtemporal-presigmoidal approach for Group I tentorial notch meningiomas; and the supracerebellar-infratentorial or the suboccipital-transtentorial approaches for Group II meningiomas. Because the best surgical approach to the tentorial incisura is still a matter of debate, the anatomy of the tentorial incisura, the clinical presentation of the patients, diagnostic indications, surgical findings, and follow up are discussed, with reference to the literature.