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Song Liu, Jean Pierre Boutrand and Marc Tadie

Object. The authors investigated the effect of a collagen-based sealant, Gel Amidon Oxydé (GAO), in the prevention of epidural scar adhesions in an adult rat model of laminectomy.

Methods. Seventy-two adult Sprague—Dawley rats underwent an L5–6 laminectomy, after which the dura mater and the left L-4 and L-5 nerve roots were exposed. In the 36 animals that received GAO, the sealant was applied over the dura and around the nerve roots, and it was used to fill the laminectomy cavity before it polymerized. In 36 control animals, the same surgical treatment was performed, but the rats did not receive GAO. During the early postoperative period, a significant decrease in the occurrence of epidural hematoma was found in the GAO-treated rats. In contrast to findings in control rats, a thin white connective tissue layer was found between the dura and surrounding muscles after GAO had degraded and been absorbed. One month posttreatment, no epidural scar adhesion was found between the tissue layer and the dura in the GAO-treated animals. Three months postoperatively, both gross inspection and histological examination further confirmed that formation of epidural adhesions was significantly inhibited in the rats treated with GAO. No special inflammatory reaction was observed, and the healing of skin and muscle lesions was not affected by either treatment.

Conclusions. The data obtained in this study suggest that the GAO collagen—based sealant may be an effective biomaterial to prevent epidural adhesions in vivo after laminectomy.

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Xue-song Liu, Chao You, Ma Lu and Jia-gang Liu

Object

A growing skull fracture (GSF) is a rare but significant late complication of skull fractures, usually occurring during infancy and early childhood. Delayed diagnosis and improper treatment could exacerbate this disease. The aim of this study was to introduce a new hypothesis about, describe the stages of, and discuss the treatment strategy for GSF.

Methods

The authors performed a retrospective review of 27 patients with GSF, who were grouped according to 3 different GSF stages.

Results

Over a period of 20 years, 27 patients with GSF (16 males and 11 females) were treated in the authors' department. The mean follow-up period was 26.5 months. Six patients were in the prephase of GSF (Stage 1), 10 patients in the early phase (Stage 2), and 11 in the late phase (Stage 3). All patients underwent duraplasty. All 6 patients at Stage 1 and 5 patients at Stage 2 underwent craniotomy without cranioplasty. Five patients at Stage 2 and all of the patients at Stage 3 underwent cranioplasty with autologous bone and alloplastic materials, respectively. Among all patients, 5 underwent ventriculoperitoneal shunt placement.

Symptoms in all patients at Stages 1 and 2 were alleviated or disappeared, and the cranial bones developed without deformity during follow-up. Among patients with Stage 3 GSF, no obvious improvement in neurological deficits was observed. Three patients underwent additional operations because of cranial deformation or infection.

Conclusions

The authors identify the stages of GSF according to a new hypothesis. They conclude that accurately diagnosing and treating GSF during Stages 1 and 2 leads to a better prognosis.

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Xiaomin Liu, Desheng Xu, Yipei Zhang, Dong Liu and Guoxiang Song

Object

This study was undertaken to evaluate clinical outcomes and tumor control in patients harboring orbital cavernous hemangiomas (OCHs) that had been diagnosed based on findings of imaging studies and treated by Gamma Knife surgery (GKS).

Methods

Between 1995 and 2008, 23 patients harboring OCHs that had been diagnosed on the basis of imaging findings were treated using GKS; complete follow-up data are available in all cases. The median treatment volume was 1.5 cm3 (range 0.15–10.10 cm3), the median tumor margin dose was 15 Gy (range 12–20 Gy), and the median follow-up period was 12 months (range 6–120 months).

Results

A decrease in tumor size was found in 20 patients, and no tumor progression was observed after GKS. Eleven of 14 patients whose visual function had been adversely affected prior to treatment had improved visual acuity at the last assessment. Side effects of the procedure included orbital pain in 3 patients and chemosis in 2 patients.

Conclusions

In this preliminary experience, GKS proved to be an effective treatment for OCHs diagnosed on the basis of imaging findings. Additional follow-up is necessary, and the long-term side effects of the procedure still need to be determined.

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Wei Qu, Dingjun Hao, Qining Wu, Zongrang Song and Jijun Liu

Unilateral facet dislocation at the subaxial cervical spine (C3–7) in children younger than 8 years of age is rare. The authors describe a surgical approach for irreducible subaxial cervical unilateral facet dislocation (SCUFD) at C3–4 in a 5-year-old boy and present a literature review. A dorsal unilateral approach was applied, and a biodegradable plate was used for postreduction fixation without fusion after failed conservative treatment. There was complete resolution of symptoms and restored cervical stability. Two years after surgery, the patient had recovered range of motion in C3–4. In selected cases of cervical spine injury in young children, a biodegradable plate can maintain reduction until healing occurs, obviate the need to remove an implant, and recover the motion of the injured segment.

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Song Liu, Jean Pierre Boutrand, Jacques Bittoun and Marc Tadie

Object. The authors investigated the effect of a collagen-based sealant, Gel Amidon Oxydé (GAO), in preventing the reformation of epidural scar adhesions in an adult rat model of laminectomy.

Methods. Thirty-two adult Sprague—Dawley rats underwent a complete L5–6 laminectomy, after which the dura mater was exposed and the left adjacent L-4 and L-5 nerve roots were exposed. The surgical wound was then closed; 1 month later it was reopened. The epidural scar adhesions that developed were observed and carefully removed, leaving clean dura and nerve roots reexposed. In 16 experimental rats, GAO was placed onto the reexposed dura and around the nerve roots before it polymerized. No treatment was performed in 16 control rats. Postoperatively, all rats were healthy and without neurological deficit. The incisions healed within 1 week regardless of the treatment with the GAO. Three months after reoperation, magnetic resonance imaging revealed that important epidural adhesions were present in the control rats but not in the experimental rats. These findings were then confirmed by gross anatomical examination in which a white tissue layer was found over the dura without adhesions in the experimental animals, whereas significant epidural scar adhesions were demonstrated in the controls. Histological evaluation of the laminectomy site also showed that the peridural space in the experimental rats was larger than that in the controls.

Conclusions. The authors found that GAO may be a safe and effective antiscarring adhesion biomaterial in vivo. When placed into the laminectomy site, GAO may prove beneficial in preventing the formation and reformation of epidural scar adhesions in humans.

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Song Liu, Nozar Aghakhani, Nazaire Boisset, Gérard Said and Marc Tadie

Object. The authors conducted a study to determine the effects of using a nerve autograft (NAG) to promote and guide axonal regrowth from the rostral spinal cord to the caudal lumbar ventral nerve roots to restore hindlimb motor function in adult marmosets after lower thoracic cord injury.

Methods. Nine animals underwent a left-sided hemisection of the spinal cord at T-12 via left-sided T9—L3 hemilaminectomy, with section of all ipsilateral lumbrosacral ventral nerve roots. In the experimental group (five animals), an NAG obtained from the right peroneal nerve was anastomosed with the sectioned and electrophysiologically selected lumbar ventral roots (left L-3 and L-4) controlling the left quadriceps muscle and then implanted into the left ventrolateral T-10 cord. In the control group (four animals), the sectioned/selected lumbar ventral roots were only ligated.

After surgery, all marmosets immediately suffered from complete paralysis of their left hindlimb. Five months later, some clinical signs of reinnervation such as tension and resistance began to appear in the paralyzed quadriceps of all experimental animals that received autografts. Nine months postoperatively, three of the five experimental marmosets could maintain their lesioned hindlimb in hip flexion. Muscle action potentials and motor evoked potentials were recorded from the target quadriceps in all experimental marmosets, but these potentials were absent in the control animals. Horseradish peroxidase retrograde labeling from the distal sectioned/reconnected lumbar ventral roots traced 234 ± 178 labeled neurons in the ipsilateral T8–10 ventral horn, mainly close to the NAG tip. Histological analysis showed numerous regenerating axons in this denervated/reconnected nerve root pathway, as well as newly formed motor endplates in the denervated/reinnervated quadriceps. No axonal regeneration was detected in the control animals.

Conclusions. These data indicate that the rostral spinal neurons can regrow into the caudal ventral roots through an NAG, thereby innervating the target muscle in adult marmosets after spinal cord injury.

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Xin Yu, Jianning Zhang, Rui Liu, Yaming Wang, Hongwei Wang, Peng Wang, Jinhui Chen and Song Liu

OBJECT

The treatment for giant posterior fossa cystic craniopharyngiomas remains an important challenge in neurosurgery. The authors evaluated the effects of treating 20 patients with giant posterior fossa cystic craniopharyngiomas using phosphorus-32 (P-32) interstitial radiotherapy at their hospital.

METHODS

The patients included 11 boys and 9 girls with an age range of 3 to 168 months. Before treatment, the tumor volumes ranged from 65 to 215 ml. The intracranial pressure was increased in 16 patients, and optic nerve damage had occurred in 18. The patients received P-32 interstitial radiotherapy following stereotactic cyst-fluid aspiration or drainage and were followed up for 7–138 months.

RESULTS

The treatment immediately relieved the intracranial hypertension symptoms in all patients. At the end of follow-up, imaging examinations revealed that the cystic tumors had disappeared, but some residual calcification remained in 12 patients, and had decreased by more than 75% of the initial volume in 8 patients. The damaged optic nerve recovered in 3 cases, improved in 12 cases, remained unchanged in 1 case, and was aggravated in 2 cases. No other severe complications related to surgery or interstitial radiation occurred. During the follow-up period, 7 new cysts appeared in 5 patients who had received additional interstitial radiotherapies with a dose of P-32 that was calculated using the same formula as for the initial treatment. The new tumors then disappeared in 2 patients, significantly shrank in 2 patients, and progressed in 1 patient.

CONCLUSIONS

For treating giant posterior fossa cystic craniopharyngiomas, P-32 interstitial radiation after stereotactic cyst-fluid aspiration or drainage can achieve a high tumor control rate and has relatively satisfactory clinical effects and quality of life outcomes with few complications.

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Dong Liu, Desheng Xu, Zhiyuan Zhang, Yipei Zhang, Yanhe Li, Xiaomin Liu, Qiang Jia, Ligao Zheng and Guoxiang Song

Object

The goal of this study was to assess the long-term results of Gamma Knife surgery (GKS) in patients harboring an optic nerve sheath meningioma (ONSM).

Methods

Thirty patients harboring an ONSM were treated with GKS between 1998 and 2003. Gamma Knife surgery was performed as the sole treatment option in 21 of these patients and resection had been performed previously in 9 patients. The mean volume of the tumor at the time of GKS was 3.6 cm3 (range 1.4–9.7 cm3), and the mean prescription peripheral dose was 13.3 Gy (range 10–17 Gy). The mean number of isocenters used to treat these lesions was 8 (range 5–14 isocenters).

Results

At a median follow-up of 56 months, visual acuity improved in 11 patients, remained stable in 13 patients (including 4 patients who were completely blind before GKS), and deteriorated in 6 patients. Follow-up images were available in all patients and showed tumor regression in 20 patients and stable tumor in 8 patients. Persistent imaging evidence of progression was only present in 2 patients. With the exception of reversible conjunctival edema in 4 cases, no other serious acute side effect was observed.

Conclusions

Gamma Knife surgery provides long-term tumor control for ONSM. The results of this study add substantial evidence that GKS may definitely become a standard treatment approach in selected cases of ONSM.

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Desheng Xu, Dong Liu, Zhiyuan Zhang, Yipei Zhang, Yanhe Li, Xiaomin Liu, Qiang Jia, Ligao Zheng and Guoxiang Song

Object

The authors evaluated the results they obtained using Gamma Knife surgery (GKS) in patients with orbital tumors.

Methods

This is a retrospective clinical evaluation of 202 patients with orbital tumors who were treated with GKS between September 1995 and October 2008. The series included 84 men and 118 women with a mean age of 39.5 ± 14.6 years (range 5–85 years). The diagnoses were determined based on pathological analyses in 113 patients and presumed based on characteristic clinical and imaging findings in 89 patients. There were 84 meningiomas, 38 epithelial tumors of the lacrimal gland, 23 schwannomas, 18 malignant choroidal melanomas, 12 optic nerve gliomas, 11 orbital metastases, 10 pseudotumors of the orbit, 3 retinoblastomas, and 3 cases of fibromatosis. The median target volume was 5.4 cm3 (range 0.04–35.6 cm3). The tumor margin dose ranged from 10 to 40 Gy.

Results

At a median follow-up period of 34.5 ± 14.7 months (range 12–114 months), tumor shrinkage was observed in 118 patients (58.4%) and stable tumor size in 71 patients (35.1%). Regularly scheduled neuroimaging studies demonstrated evidence of tumor progression in only 13 patients (6.4%): 9 of these patients underwent repeated GKS and 4 received surgical treatment. Visual acuity was preserved in 129 patients. Seventy-two patients experienced some degree of improvement in vision. Severe deterioration of visual acuity was found in 18 of 147 patients who had useful vision before treatment. Nineteen patients (9.4%) experienced transient conjunctival edema; no other serious acute side effect was observed.

Conclusions

Gamma Knife surgery provides an effective management strategy in patients with orbital tumors; it achieves excellent preservation of neurological function and is associated with few treatment-related complications.

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Song-tao Qi, Yi Liu, Jun Pan, Silky Chotai and Lu-xiong Fang

Object

The completeness of meningioma resection depends on the resection of dura mater invaded by the tumor. The pathological changes of the dura around the tumor can be interpreted by evaluating the dural tail sign (DTS) on MRI studies. The goal of this study was to clarify the pathological characteristics of the DTSs, propose a classification based on the histopathological and radiological correlation, and identify the invasive range of tumor cells in different types of DTS.

Methods

The authors retrospectively reviewed 179 patients with convexity meningiomas who underwent Simpson Grade I resection. All patients underwent an enhanced MRI examination preoperatively. The convexity meningiomas were dichotomized into various subtypes in accordance with the 2007 WHO classification of tumors of the CNS, and the DTS was identified based on the Goldsher criteria. The range of resection of the involved dura was 3 cm from the base of the tumor, which corresponded with the length of DTS on MRI studies. Histopathological examination of dura at 0.5, 1.0, 1.5, 2.0, 2.5, and 3.0 cm from the base of the tumor was conducted, and the findings were correlated with the preoperative MRI appearance of the DTS.

Results

A total of 154 (86%) of 179 convexity meningiomas were classified into WHO Grade I subtype, including transitional (44 [28.6%] of 154), meningothelial (36 [23.4%] of 154), fibrous (23 [14.9%] of 154), psammomatous (22 [14.3%] of 154), secretory (10 [6.5%] of 154), and angiomatous (19 [12.3%] of 154). The other 25 (14%) were non–Grade I (WHO) tumors, including atypical (12 [48%] of 25), anaplastic (5 [20%] of 25), and papillary (8 [32%] of 25). The DTS was classified into 5 types: smooth (16 [8.9%] of 179), nodular (36 [20.1%] of 179), mixed (57 [31.8%] of 179), symmetrical multipolar (15 [8.4%] of 179), and asymmetrical multipolar (55 [30.7%] of 179). There was a significant difference in distribution of DTS type between Grade I and non–Grade I tumors (p = 0.004), whereas the difference was not significant among Grade I tumors (0.841) or among non–Grade I tumors (p = 0.818). All smooth-type DTSs were encountered in Grade I tumors, and the mixed DTS (52 [33.8%] of 154) was the most common type in these tumors. Nodular-type DTS was more commonly seen in non–Grade I tumors (12 [48%] of 25). Tumor invasion was found in 88.3% (158 of 179) of convexity meningiomas, of which the range of invasion in 82.3% (130 of 158) was within 2 cm and that in 94.9% (150 of 158) was within 2.5 cm. The incidence of invasion and the range invaded by tumor cells varied in different types of DTS, and differences were statistically significant (p < 0.001).

Conclusions

Nodular-type DTS on MRI studies might be associated with non–Grade I tumors. The range of dural resection for convexity meningiomas should be 2.5 cm from the tumor base, and if this extent of resection is not feasible, the type of DTS should be considered. However, for skull base meningiomas, in which mostly Simpson Grade II resection is achieved, the use of this classification should be further validated. The classification of DTS enables the surgeon to predict preoperatively and then to achieve the optimal range of dural resection that might significantly reduce the recurrence rate of meningiomas.