Image directed stereotactic surgery for brain stem lesions

Summary Advances in neurological imaging may have increased the diagnostic accuracy and the detection rate of intrinsic brain stem lesions, but a histological diagnosis is still an essential requirement for rational and appropriate management. Open exploration allows biopsy and resection in cases where an exophytic component is present. The surgical inaccessibility and the resultant morbidity of these approaches, however, associated with a low diagnostic yield in cases with no visible surface abnormality, are important limiting factors.A series of 45 brain stem lesions stereotactically approached with CT or MRI guidance is presented. A transcortical frontal pre-coronal trajectory was used in all of them. Haematoma was preoperatively diagnosed in 10 cases and the procedure was for therapeutic aspiration. Of 35 cases where the diagnosis was uncertain, although intrinsic tumour was suspected, positive results were obtained in 33, while unexpected findings of granuloma, lymphoma, angioma, leucoencephalopathy, vasculitis and radiation necrosis were found in over 10% of the cases. There were no operative deaths and the morbidity was low. In no case was there a permanent neurological deterioration directly related to the procedure, although there was a transient deterioration in two patients and one patient required early reaspiration of a haematoma.Image directed stereotactic approaches to brain stem lesions can combine a high degree of accuracy (offering positive histological diagnoses) with a low operative morbidity. MRI directed biopsies can complement CT guided ones thus increasing the number of suitable cases and improving the success rate. The frontal precoronal transcortical trajectory provides safe access to the majority of the brain stem targets.Invited Lecture, presented at the European Congress of Neurosurgery, Moscow, June 23–29, 1991.     

CT-guided stereotactic aspiration of brain abscesses

The effective treatment of intracranial abscess remains controversial. Progress in technology, linked with the development of neuronavigational systems, has made stereotactic aspiration and drainage of intracerebral abscesses effective and valid alternatives to traditional methods, namely, conservative medical treatment or open surgical excision. Between 1995 and 2002, 12 patients at our hospital underwent drainage of intracerebral abscesses under stereotactic guidance. Ten patients had solitary lesions and two had multiple abscesses. The appropriate antibiotic schemes were administered following culture of the aspirated material. The size of the abscess, the mass effect, and response to antibiotic treatment were followed up by repeated CT scans. All patients showed improvement and, at the end of treatment, returned to their previous activities. There were neither deaths nor any postoperative complication. A second aspiration was required in one patient due to recurrence of the abscess. The CT-guided stereotactic aspiration of brain abscesses helps achieve all treatment goals. It drains the contents of the abscess, reduces mass effect, and confirms diagnosis. It is minimally invasive, carries minimal morbidity and mortality, and can be performed on compromised patients under local anesthesia.     

CT-guided stereotactic aspiration and treatment of brain abscesses

Summary The present study reports our experience with stereotactic puncture, aspiration and drainage of brain abscesses in 24 patients from a series of 34 consecutive cases. In all patients an intracavitary catheter was left in place for external drainage and daily irrigation with antibiotics. The patients received pre- and postoperatively triple broad spectrum antibiotic treatment, associated with low dose steroids and anti-epileptic drugs. Follow-up CT scans showed immediate reduction of the abscess size and gradual diameter diminution of the enhancing ring structure until its disappearance. The clinical presentation, risk factors, aetiology, outcome, bacteriological and CT findings were analysed. Mortality in this series was 4%. The majority of patients (96%) had no or minimal disability according to the Glasgow Outcome Scale. Our results confirm the value of this treatment policy and suggest that the stereotactic technique is a simple and safe method with minimal mortality and morbidity in the treatment of the majority of chronic brain abscesses.     

Modified screw-and-suction technique for stereotactic evacuation of deep intracerebral hematomas

A new “screw-and-suction” device modified from Backlund's prototype for stereotactic evacuation of intracerebral hematoma is described. This modification can facilitate the evacuation of the hematoma in a smooth and gentle manner. The instrument has been applied to six patients with intracerebral hematomas in the basal ganglia region. Of these patients, five recovered to a satisfactory condition and one died. Our preliminary experience shows that most of the hematomas can be effectively evacuated by a computed tomography-guided stereotactic technique. The procedure may be indicated as an alternative treatment for high-risk patients with deep-seated hematomas.     

Gamma knife surgery for brain metastases: indications for and limitations of a local treatment protocol

Summary Objective. The purpose of this retrospective study was to evaluate results of a local treatment protocol using gamma knife surgery (GKS) for brain metastases without upfront whole brain radiation therapy (WBRT).Methods. Results for 521 consecutive patients satisfying the following 3 criteria were analysed: 1) a maximum of 3 tumours with a diameter of 25 mm or more; 2) no prior WBRT; 3) no surgically in accessible large (>30 mm) tumours. Large tumours were surgically removed and all smaller lesions were treated by GKS without up front WBRT. New lesions, detected with follow-up MRI, were appropriately treated with repeat GKS. Overall survival (OS), neurological survival (NS), qualitative survival (QS) and new lesion-free survival (NLFS) curves were calculated and the prognostic values of covariates were obtained. OS and NS were compared according to tumour number.Results. In total, 1023 separate sessions were required to treat 4562 lesions. The primary organs were lung in 369 patients, gastro-intestinal tract in 70, breast in 33, urinary tract in 24, and others/unknown in 25. The median OS period was 9.0 months. On multivariate analysis, the significant prognostic factors for OS were found to be extracranial disease (risk factor: active), Karnofsky performance status (KPS) score (<70) and gender (male). NS and QS at one year were 85.6% and 73.0%, respectively. The only significantly poor prognostic factor for NS was carcinomatous meningitis. NLFS at 6 months was 68.9%. For both OS and NS, the differences between a few (≤3) and many (4–10) brain lesions were not significant (OS: p=0.3128, NS: p=0.5509). Patients with numerous (>10) tumours had a significantly poorer prognosis than those with ≤10.Conclusion. Our protocol, aggressively applying GKS, provides excellent results in selected patients with ≤10 brain lesions and no carcinomatous meningitis.     

Diffusion-weighted MR imaging in the preoperative assessment of brain abscesses

BACKGROUND

Diffusion-weighted MR imaging (DWI) has recently shown promise in differentiating ring-enhancing lesions such as brain abscess and malignant neoplasm. The ability of DWI to strongly suggest brain abscess enables a neurosurgeon to alter stereotactic planning to optimize diagnosis. We report our experience with DWI in 5 patients with lesions on MR imaging and review the literature to assess the usefulness of this technique in the preoperative evaluation of cerebral abscess.

METHODS

The MR images of 5 patients presenting with ring-enhancing lesions that ultimately proved to be brain abscesses were retrospectively reviewed. In addition to standard MR sequences, trace DWI and apparent diffusion coefficient (ADC) calculations were performed on all patients. Additionally, 15 recently published articles or references in press concerning DWI in cerebral abscesses were reviewed.

RESULTS

All lesions were markedly hyperintense on DWI and had diminished ADC. Thirty-eight of 39 previously reported abscesses were hyperintense on DWI with reduced ADC. Of 165 nonpyogenic lesions with DWI findings, 87 were hypointense or isointense, 78 lesions had variable hyperintensities, and few manifested the degree of hyperintensity observed with abscesses. Most of these included chordomas and epidermoids, which are not likely to be confused with abscesses.

CONCLUSIONS

Restricted water diffusion, as indicated by hyperintensity on DWI and low ADC, in ring-enhancing lesions assists in differentiating brain abscess from necrotic tumor. This information facilitates stereotactic surgical planning: abscesses should be preferentially centrally aspirated, whereas necrotic brain tumors should have diagnostic tissue biopsied from cavity walls. Although not definitive for brain abscess, restricted water diffusion is an important MR imaging sign and is useful in neurosurgical treatment strategies for ring-enhancing lesions.     

立体定向脑内病灶活检的临床意义

目的 探讨先进图像引导立体定向脑组织活检术方法 ,明确其在神经系统疾病诊断中的意义.方法 回顾性分析1987年12月至2009年1月立体定向脑内病灶活检的1187例病历资料,其中男性694例(58.5%),女性493例(41.5%);年龄1～85岁(平均39.7岁).CT(含正电子发射断层扫描)引导活检607例,MRI(含氢质子磁共振波谱成像)引导活检580例;采用常规框架立体定向活检手术726例,采用无框架立体定向机器人活检手术461例(含定向引导神经内镜活检).早期450例立体定向手术定位,采用CT或MRI图像测量靶点坐标方法 ,不能立体显示穿刺途径;后期737例立体定向手术定位,采用计算机三维重建病灶方法 ,能够立体显示穿刺路径.结果 活检明确组织病理学诊断1156例(活检阳性诊断率97.4%).本组中983例(82.8%)获得肿瘤学病理诊断,主要包括神经胶质瘤、转移性肿瘤、原发性淋巴瘤、生殖细胞瘤等;173例(14.6%)为非肿瘤性病变,其中包括多发硬化和瘤样脱髓鞘病变、神经变性疾病、炎性病变、寄生虫病等.活检穿刺手术并发少量血肿(<10 ml)而无神经功能障碍20例(1.7%),较大血肿(>10ml)需要外科处理(置管引流或开颅血肿清除)9例(0.8%);活检出血导致死亡3例(0.3%).本组无颅内感染病例.结论 先进影像技术引导的立体定向脑组织活检术是一种微侵袭、可靠的脑内疾病确定诊断手段.生化成像、功能成像技术的发展,为立体定向引导的活检技术赋予了崭新的内容.     

Haemorrhagic complications and the incidence of asymptomatic bleeding associated with stereotactic brain biopsies

Summary Object. Stereotactic brain biopsy is a routinely used technique for the diagnosis of brain lesions. Due to its minimally invasive nature, the potential risks associated with this procedure are sometimes underestimated. We have retrospectively analyzed the incidence of symptomatic and asymptomatic haemorrhagic complications associated with stereotactic biopsies. Various variables that may contribute to such complications have been retrospectively analyzed.Methods. Medical and radiological records of 355 consecutive patients who underwent a diagnostic stereotactic brain biopsy were reviewed. The incidence of haemorrhage was derived from a routine post-operative CT scan done within 90–120 minutes of the biopsy. Demographic, radiographic, pathological, and clinical data were also extracted and evaluated for their possible association with haemorrhagic complications.Results. Twenty-five patients (7%) experienced haemorrhagic complications associated with stereotactic biopsy, about half of whom (3.4%) were asymptomatic with no impact on the clinical course. Thirteen (3.6%) complications were symptomatic and two patients (0.6%) died. Lesions located in the brainstem were found to have a significantly higher rate of complications compared to other locations. No other variables, such as location, edema, number of biopsy specimens, or pre-existing neurological deficit showed a statistically significant impact on the incidence or severity of haemorrhage. Seven of the symptomatic complications occurred immediately post biopsy, but in six patients they developed within several hours and even days. The overall diagnostic yield of the biopsies was 93.8%, but was somewhat lower in patients experiencing a haemorrhagic complication.Conclusions. Stereotactic brain biopsy was associated with a low incidence of symptomatic haemorrhagic complications, morbidity and mortality, and a high diagnostic yield. About half of the haemorrhagic complications were asymptomatic. Lesions located in the brainstem had a higher rate of complications. No other clinical, radiographic, or pathological variables were found as predictors of increased risk for haemorrhage.     

Multiple streptococcal brain abscesses successfully treated by craniotomy and needle aspiration

The successful surgical treatment of multiple brain abscesses by means of needle aspiration is reported. There is a need for aggressive surgical and antibiotic treatment, using local anesthesia and needle aspiration, when fully developed abscesses are present. The computerized tomographic scan and related surgical techniques allow for a precise localization of an abscess and its evacuation even if it is located in so-called vital areas of the brain.     

Accuracy of stereotactic brain tumor biopsy: Comparison of the histologic findings in biopsy cylinders and resected tumor tissue

Appropriate treatment for intracranial mass lesions depends upon accurate morphological diagnosis. In 47 of 360 patients the findings in stereotactically obtained tissue cylinders were compared with tumor resection (n=38) or autopsy (n=9) tissue material to define the accuracy of our stereotactic biopsy method. These biopsies were performed using the LEKSELL CT stereotactic frame and a spiral needle which procured about 10-mm-long tissue cylinders. Usually, three to four successive biopsy specimens were taken along the target trajectory placed through the whole lesion and its margins according to the CT imagings. Final morphological diagnosis was exclusively based on the histological findings of permanent paraffin sections.In 42 cases (89%), the histological results in biopsy and resection/autopsy tissue were identical, including mainly cases of low and high grade gliomas as well as some brain lymphomas, metastases, and cases of inflammatory brain lesions (aspergillosis, toxoplasmosis). In 3 patients with a diagnosis of brain lymphoma and low grade glioma on the basis of the surgical specimens, stereotactic biopsy revealed only unspecific reactive tissue changes. In two cases of the early part of the study, sampling errors occurred. This study provides evidence for the high diagnostic accuracy of the established stereotactic biopsy method which is characterized by representative tissue sampling and histological processing of the specimens.     

Factors that enhance the likelihood of successful stereotactic treatment of brain abscesses

Summary Successful clinical outcomes are not achieved in all patients who undergo image-guided stereotactic surgery as the initial procedure in the management of brain abscess. We sought to define those factors related to management failure, so that the initial surgical approach could be selected using preoperative clinical or imaging criteria. We reviewed our twelve-year experience in 29 consecutive patients. Twenty-two (76%) patients had drainage of abscesses with purulent centers. Seven (24%) underwent lesion biopsy for diagnosis. Twelve patients (with abscesses >3 cm in average diameter) underwent stereotactic insertion of drainage catheters. Ten patients (34%) had adverse risk factors including immunologic suppression after prior organ transplantation, chronic steroid therapy, prior antineoplastic chemotherapy, or retained foreign body. Microbiological identification of the causative organism was obtained in 22 patients; 6 patients had positive Gram stains without growth in culture (bacteriological diagnosis=97%). Long-term clinical evaluation (up to 8.5 years, median 3 years) confirmed disease resolution after initial single-procedure stereotactic management in 21 patients (72%). Eventual abscess resolution occurred in an additional 6 patients (21%), all of whom required multiple procedures. Five patients died of complications of their systemic disease during the follow-up period. Fifteen of the 18 (83%) surviving patients who had no associated risk factors returned to their premorbid functional capacity. Factors associated with initial treatment failure included inadequate aspiration, lack of catheter drainage of larger abscesses, chronic immunosuppression, and insufficient antibiotic therapy.     

Hardware-related complications of deep brain stimulation: a ten year experience

Summary Objective. To analyse the occurrence of hardware-related complications in patients with deep brain stimulation (DBS), over a long period of time. Method. All patients operated on with DBS at our institution between 1993 and 2002 were followed with respect to adverse events related to the implanted hardware. Results. One hundred and nineteen consecutive patients underwent 139 procedures with implantation of 161 electrodes. The minimum follow-up was 12 months. The follow-up time was 540 electrode-years. The rate of hardware-related complications per electrode-year was 4.3%. In total, 17 patients (15%) had 23 hardware-related complications. These included 8 electrode breakages, 4 electrode migrations, 2 stimulator migrations, 3 erosions, 2 erosions and infections, 2 infections and 2 cases of stimulator malfunction. The majority of these complications occurred during the first four years in our experience. Conclusions. DBS is a life-long therapy that requires a life-long follow-up. Increased experience and adaptation of surgical technique are the main determinants for avoidance of hardware-related complications.     

Defining the Role of Stereotactic Radiosurgery Versus Microsurgery in the Treatment of Single Brain Metastases

Summary  Stereotactic radiosurgery (RS) and surgery have proved to be effective treatment modalities for brain metastasis. We followed 133 patients whose treatment for intracranial disease was either RS or a single surgical resection at the University of Vienna from August 1992 through October 1996. All patients who received additional Whole Brain Radiotherapy were included. This was a retrospective, case-control study comparing these treatment modalities.  Sixty-seven patients were treated by RS and 66 patients were treated by microsurgery. The median size of the treated lesions for RS patients was 7800 mm³, and 12500 mm³ for microsurgery patients, respectively. The median dose delivered to the tumour margin for RS patients was 17 gray.  The median survival for patients after RS was 12 months, and 9 months for patients after microsurgery. This difference was not statistically significant (p=0.19). Comparison of local tumour control, defined as absence of regrowth of a treated lesion, showed that tumours following RS had a preferred local control rate (p<0.05). Univariate and multivariate analysis showed that this fact was due to a greater response rate of “radioresistant” metastasis to RS (p<0.005). Postradiosurgical complications included the onset of peritumoural oedema (n=5) and radiation necrosis (n=1). Two patients after microsurgery experienced local wound infection. One postoperative death occurred due to pulmonary embolism in this group.  On the basis of our data we conclude that RS and microsurgery combined with Whole Brain Radiotherapy are comparable modalities in treating single brain metastasis. Concerning morbidity and local tumour control, in particular in cases of “radioresistant” primary tumours, RS is superior. Therefore we advocate RS except for cases of large tumours (>3 cm in maximum diameter) and for those with mass effect.     

Successful medical treatment of multiple brain abscesses due to Nocardia farcinica in a paediatric renal transplant recipient

Brain abscesses caused by Nocardia are rare, but it is very important to detect and treat them early because the associated mortality is 3 times higher than that associated with other bacterial brain abscesses. This infection is prevalent among adults on long-term immunosuppressive therapy; we report the case of a male kidney transplant recipient aged 12.7 years who developed early multiple Nocardia-induced brain abscesses that were successfully treated with linezolid, a novel antibiotic therapy.     

Comparison of accuracy and precision between frame-based and frameless stereotactic navigation for deep brain stimulation electrode implantation

The accuracy and precision of frameless neuronavigation as compared to conventional frame-based stereotaxy for implantation of deep brain stimulation (DBS) electrodes were studied in 14 patients with essential tremor. DBS electrodes were implanted bilaterally in the ventrolateral thalamus [ventrointermediate nucleus (VIM)] in one procedure. Frameless neuronavigation was used on one side and the conventional frame-based technique on the other. Targeting was guided by MRI and CT imaging. Intraoperative stereotactic plain X-ray verified final electrode positions and electrode deviations from the planned target were measured. Clinical outcome was evaluated with the Essential Tremor Rating Scale. Thirteen of the patients were eligible for measuring electrode deviations and 10 of them were available for a clinical follow-up. Electrode deviations from target were larger using the frameless technique in the medial-lateral (x: 1.9 +/- 1.3 mm) and anterior-posterior (y:0.9 +/- 0.8 mm) directions as compared to the frame-based technique (x: 0.5 +/- 0.5 and y: 0.4 +/- 0.4 mm) but similar in the superior-inferior direction (z). The vector of deviation was 2.5 +/- 1.4 mm with the frameless technique and 1.2 +/- 0.6 with the frame-based technique. The differences were statistically significant (p < 0.05-0.001). The dispersion was larger with the frameless technique as represented by the larger standard deviations in all three planes. At clinical follow-ups, tremor reduction was similar irrespective of the implantation technique. It is concluded that conventional frame-based stereotaxy has higher accuracy/precision for hitting a small brain target than the frameless technique. However, the difference is relatively small and does not influence the clinical result of DBS electrode implantations in the VIM when treating tremor.     

Towards construction of an ideal stereotactic brain atlas

Summary Background. The role of the brain atlas is changing in many aspects with the advancements in stereotactic and functional neurosurgery. Therefore, there is a critical need to construct a new atlas. This paper addresses the definition and construction of an atlas, ideal (in our opinion) for stereotactic and functional neurosurgery. The essence of the new atlas is not only its population-based structural and functional content, but also its continuous “self-updatability” with the new clinical results obtained. Method. The ideal atlas defined here contains four major components: brain models, knowledge database, tools, and clinical results. Towards its creation, a multi-atlas is proposed. The construction of the initial version of the multi-atlas is detailed with the probabilistic functional atlas (PFA), interpolated Talairach-Tournoux atlas, and enhanced Schaltenbrand-Wahren atlas. These atlases are put in a spatial register by matching their AC-PC distances and heights of the thalamus; the Schaltenbrand coronal and sagittal microseries are scaled laterally to match the target structure centroids with the locations of the best targets of the PFA. Findings. Construction of an initial version of the ideal stereotactic atlas is feasible at present from the available resources. To achieve that, our three atlases (PFA, Talairach and Schaltenbrand) are enhanced and combined together. A single lateral scaling factor per target structure is feasible to co-register the Schaltenbrand atlas with PFA in four situations (compensated against the third ventricle, non-compensated, bilateral, and non-bilateral). The STN has to be stretched by 18% more than the VIM on the Schaltenbrand coronal microseries, and the VIM has to be compressed by 13% less than the STN on the Schaltenbrand sagittal microseries. Conclusion. The new multi-atlas can potentially be more useful than the currently employed atlases and will facilitate further development of the ideal atlas for stereotactic and functional neurosurgery. Correspondence: Wieslaw L. Nowinski, DSc, PhD, Biomedical Imaging Lab, Agency for Science Technology and Research, 30 Biopolis Street, #07-01 Matrix, 138671 Singapore.     

护理干预对颅脑术后昏迷患者下肢深静脉血栓形成的影响

目的观察护理干预对颅脑术后昏迷患者下肢深静脉血栓形成的影响,改善患者临床预后。方法将76例颅脑术后昏迷患者按不同护理方法均分为观察组和对照组,对照组进行Routineeare,观察组在对照组的基础上再给予预防双下肢深静脉血栓形成的护理措施,比较两组下肢深静脉血栓发生率、下肢肿胀发生率、肺栓塞发生率。结果观察组和对照组的下肢深静脉血栓发生率、下肢肿胀发生率、肺栓塞发生率分别为2．63％（1／38）比15．79％（6／38）,5．26％（2／38）比21．05％（8／38）,0（0／38）比2．63％（1／38）,观察组下肢深静脉血栓发生率、下肢肿胀发生率明显低于对照组（均P〈0．05）。结论护理干预能够降低颅脑术后昏迷患者下肢深静脉血栓形成的发生率及下肢肿胀发生率,改善临床预后,减轻患者痛苦,值得临床推广使用。     

A quick and universal method for stereotactic visualization of the subthalamic nucleus before and after implantation of deep brain stimulation electrodes

For deep brain stimulation (DBS) of the subthalamic nucleus (STN), it would be an advantage if the STN could be visualized with fast acquisition of MR images, allowing direct and individual targeting. We present a protocol for T2-weighted, nonvolumetric fast-acquisition MRI, implemented at 8 centers in 6 countries. Acquisition time varied between 3 min 5 s and 7 min 48 s according to the center, and imaging often provided visualization of the STN on axial and coronal scans. Postoperatively, the same imaging protocol permitted visualization of the target area and DBS electrodes with minimum artifacts. This imaging technique may contribute to a decrease in the number of electrode passes at surgery.