Early diagnosis of external ventricular drainage infection: results of a prospective study

OBJECTIVES: The aim of this study was to evaluate the influence of total drainage time on the risk of catheter infection, and the predictive value of standard laboratory examinations for the diagnosis of bacteriologically recorded cerebrospinal fluid (CSF) infection during external ventricular drainage. METHODS: During a three year period, all patients of the neurosurgical intensive care unit (ICU), who received an external ventricular drain, were prospectivly studied. Daily CSF samples were obtained and examined for cell count, glucose and protein content. Bacteriological cultures were taken three times a week, and serum sepsis parameters were determined. RESULTS: 130 patients received a total of 186 external ventricular drains. The ventricular catheters were in place from one to 25 days (mean 7.1 days). In 1343 days of drainage, the authors recorded 41 positive bacteriological cultures in 21 patients between the first and the 22nd drainage day (mean 6.4). No significant correlation was found between drainage time and positive CSF culture. The only parameter that significantly correlated with the occurrence of a positive CSF culture was the CSF cell count (unpaired t test, p<0.05). CONCLUSIONS: Drainage time is not a significant risk factor for catheter infection. Increasing CSF cell count should lead to the suspicion of bacteriological drainage contamination. Other standard laboratory parameters, such as peripheral leucocyte count, CSF glucose, CSF protein, or serum sepsis parameters, are not reliable predictors for incipient ventricular catheter infection.     

External drainage for ventricular infection following cerebrospinal fluid shunts

57 children with shunt-related ventricular infection were treated with external ventricular drainage and a combination of systemic and intraventricular antibiotics. For persistent infection or inadequate drainage volume the external ventricular drain was promptly changed. Cerebrospinal fluid cultures of 54 (95%) of the children became sterile within an average of 5.1 days. As soon as three consecutive 48-hour cultures of the cerebrospinal fluid were negative, the external ventricular drainage was removed and a new ventriculoperitoneal shunt was inserted. Provided that three consecutive 48-hour cultures of the cerebrospinal fluid were negative at the time of reinstitution of ventriculoperitoneal shunting, low cerebrospinal fluid glucose readings were not associated with any greater risk of recurrent infection than following primary ventriculoperitoneal shunting.     

腰大池引流加鞘内注射治疗泛耐药鲍曼不动杆菌颅内感染的临床疗效分析

目的探讨腰大池引流加鞘内注射治疗泛耐药鲍曼不动杆菌颅内感染的疗效和安全性。方法回顾性分析2018年4月—2019年12月本院神经外科收治的26例泛耐药鲍曼不动杆菌颅内感染患者的临床资料,所有患者均接受腰大池引流及鞘内注射抗生素,观察并记录患者感染指标(体温、颈项强直征、血常规、脑脊液常规及生化、脑脊液细菌培养)变化情况,记录治疗方法并对治疗效果进行分析。结果 24例患者行单纯性腰大池引流,2例患者因腰大池引流管堵塞,重置腰大池引流管并联合侧脑室引流。23例患者在治疗10～34 d内治愈,治愈率为88.46%; 3例患者死亡,死亡率11.54%,死亡时间分别为感染确认后第4天、第7天、第12天。结论对泛耐药鲍曼不动杆菌颅内感染患者应用腰大池引流加鞘内注射治疗是安全有效的,值得临床推广。如发生因脑脊液蛋白含量高导致腰大池引流管堵塞,可联合侧脑室引流并行腰大池-侧脑室方向替加环素溶液持续冲洗。     

Primary intervention for posthemorrhagic hydrocephalus in very low birthweight infants by ventriculostomy

The objective of our study was to determine the efficacy of ventriculostomy as the primary treatment for posthemorrhagic hydrocephalus in premature infants. Within a period of 4 years, 20 very low birthweight (VLBW) infants (birthweight median 1135 g, range 650–1470 g) were treated for progressive posthemorrhagic hydrocephalus (PHHC) by right parietal ventriculostomy (Salmon Rickham) at a mean age of 21 days. Serial tapping of the subcutaneous reservoir was performed for temporary drainage until conversion to a permanent ventriculoperitoneal (VP) shunt or spontaneous resolution of hydrocephalus. A total of 1402 punctures (median 71 / infant, range 13–168) was performed. The results showed that only 1/20 patients developed a cerebrospinal fluid (CSF) infection, accounting for a 5% patient-related and 0.07% procedure-related infection rate. Major complications such as skin defects, subdural hygroma, or CSF leaks occurred in three patients (15%). A permanent shunt was needed in 17 patients (85%).We concluded that, as an effective alternative to serial or lumbar puncture, there should be early implantation of ventriculostomy reservoirs for serial taps to control intracranial pressure in PHHC of VLBW infants until a permanent shunt can be placed because of the low incidence of infections and technical complications. Received: 14 February 2000 Revised: 10 May 2000     

脑室内感染的治疗体会

目的 探讨脑室内感染的治疗方法 . 方法 21例脑室内感染的患者行双侧脑室置管后,给予脑室持续灌洗引流配合全身抗感染及对症支持治疗.结果 治愈18例,死亡3例,治愈率85.7%.结论 脑室持续灌洗引流疗法配合全身抗感染及对症支持治疗可明显提高脑室内感染的治愈率.     

脑室外联合腰大池引流治疗脑室出血并发脑积水

目的总结脑室外联合腰大池引流治疗脑室出血并发脑积水的疗效。方法回顾性分析45例脑室出血并发脑积水病人的临床资料,其中采取脑室外联合腰大池引流(联合组)16例,采取单纯脑室外引流(单纯组)29例。对两组因脑积水需行脑室-腹腔分流术的病例进行统计分析。结果联合组腰大池引流时间5～25d,平均12d;脑室外引流时间4～18d,平均12d。单纯组引流时间8～24d,平均16d。术后并发颅内感染,联合组1例(6.3%),单纯组3例(10.3%);引流管堵塞或脱落,联合组和单纯组各2例。术后需行脑室-腹腔分流术,联合组3例(18.7%),单纯组10例(34.5%),两组比较差异具有统计学意义(P0.05)。结论早期脑室外联合腰大池引流是治疗脑室出血并发脑积水安全而有效的措施。     

Stereotactic neurosurgery in children and adolescents

Between March 1992 and January 1998, 100 stereotactic procedures were carried out in our Stereotactic Department. Of these, 24 were performed on patients under 18 years of age, 22 of them under a local anaesthetic and sedation. The ages of these patients ranged between 4 months and 18 years. The stereotactic procedures carried out were: 15 cerebral biopsies, 5 iodine-125 implants, 4 implantations of Rickham reservoirs with ventricular catheter, with additional holes to establish a connection between the cyst content and the ventricular system (internal drainage): 2 of these patients had arachnoidal cysts in the pineal region, 1 a thalamic neuroepithelial cyst and 1 a cystic craniopharyngioma, with excellent control of hydrocephalus. All cerebral biopsies were positive, including 3 in which brain stem tumours were detected. Of the 5 patients treated by brachytherapy, 4 had pilocytic astrocytomas and 1 an anaplastic astrocytoma. The sites of the tumours for which implants were used were the thalamus in 4 cases, and the basal ganglia (corpus striatum) in 1. In only 2 cases was there some transistory morbidity, and mortality was nil. The stereotactic procedures in this varied group were well tolerated, with low morbidity and mortality rates, which proves that this method is effective and safe for patients. It can also be used for the diagnosis of brain stem tumours. Midline cysts can also be treated by means of internal drainage with catheters (a minimally invasive form of surgery). Received: 6 November 1998     

Long subcutaneous tunnelling reduces infection rates in paediatric external ventricular drains

Purpose

The aim of this study is to report the efficacy of long subcutaneous tunnelling of external ventricular drains in reducing rates of infection and catheter displacement in a paediatric population.

Methods

In children requiring external ventricular drainage, a long-tunnelled drain was placed and managed according to a locally agreed guideline. End points were novel CSF infection incurred during the time of drainage and re-operation to re-site displaced catheters. Data were compared to other published series.

Results

One hundred eighty-one long-tunnelled external ventricular drains (LTEVDs) were inserted. The mean age was 6.6 years (range 0–15.5 years). Reasons for insertion included intraventricular haemorrhage (47 %), infection (27 %), tumour-related hydrocephalus (7.2 %), as a temporising measure (17 %) and trauma (2.2 %). The overall new infection rate for LTEVD was 2.76 %. If the 48 cases where LTEVDs were inserted to treat an existing infection are excluded, the infection rate was 3.8 % (5/133). The mean duration of insertion was 10 days (range 0–42 days). Four LTEVDs (2.2 %) were inadvertently dislodged, requiring reinsertion. Thirteen patients required removal of EVD alone. There was a significant difference (p?Conclusion The use of an antibiotic-impregnated LTEVD, managed according to a predefined guideline, is associated with significantly reduced infection and displacement rates when compared with contemporary series. It is suggested that this reduction is of both clinical and economic benefits.     

Comparison of ventricular drainage in poor grade patients after intracranial hemorrhage

OBJECTIVES: The selection of patients and treatment criteria for acute hydrocephalus and intracranial pressure (ICP) after intracranial hemorrhage remains unclear. In general neurosurgical practice, there is a tendency to use external ventricular drainage (EVD) for the patients. This study was undertaken to analyse the complications and efficiency of the different treatment modalities.METHODS: The effects, complications and outcome of ventricular drainage on high ICP and hydrocephalus were analysed retrospectively in 109 patients with intracranial hemorrhage. All the patients were assessed using the Glasgow Coma Scale, computed tomography and ICP monitoring. We excluded patients over the GCS of 8. All patients underwent a procedure for ICP monitoring plus ventricular cerebrospinal fluid (CSF) drainage. Sixty-one patients were managed with one (single) EVD system; 12 patients needed two EVD systems consecutively, while 23 patients underwent an EVD procedure followed by permanent ventriculoperitoneal (VP) shunt insertion. Thirteen patients were treated only by VP shunt for ventricular drainage. The infection rate and outcome 9 months after hemorrhage were analysed.RESULTS: The infection rates were 8.1% in the one-EVD group, 33.3% in the two-EVD group (one EVD versus two EVD, p<0.05), 8.6% in the EVD-VP group and 7.7% in the VP shunt group. The mortality rates were 73.7% in the one-EVD group, 83.8% in the two-EVD group, 47.8% (p<0.05) in the EVD-VP group and 53.8% (p<0.01) in the VP shunt group.DISCUSSION: This study indicates that single and short-term use of EVD and/or early VP shunting are associated with a low risk of infection. Furthermore, early VP shunting may protect the brain from the irregular control of intracranial hypertension and may allow more time for resolution of CSF circulation and significantly lowers the mortality rates.     

Long-term experience with subcutaneously tunneled external ventricular drainage in preterm infants

We previously reported on a series of 27 newborn infants treated for posthemorrhagic hydrocephalus with external ventricular drainage during 1984 to 1989. In the present study we continued to evaluate this technique during the subsequent 8 years (37 patients; mean birthweight 1251±478 g; mean gestational age 29±2.9 weeks; 51 drains), and we now report on the long-term experience with this method, complications, and neurodevelopmental outcome of the survivors. The mean age at drain insertion was 21 days, and the mean duration of drainage 23 days. Eight infants died of causes unrelated to external ventricular drainage. Eleven of the survivors did not require a permanent shunt. Two patients experienced ventriculitis, resulting in an infection rate of 5.4% per patient and 3.9% per drain. The neurodevelopmental outcome was mainly dependent on the extent of the pre-existing parenchymal injury. We conclude that external ventricular drainage is a safe and effective technique for the management of preterm infants with posthemorrhagic hydrocephalus.     

Sonication of catheter tips for improved detection of microorganisms on external ventricular drains and ventriculo-peritoneal shunts

The diagnosis of infections involving internal or external neurosurgical drainage devices is challenging, and to our knowledge no single reliable microbiological test exists. We used sonication to study bacterial colonization in 14 explanted external ventricular drains (EVD) and 13 ventriculo-peritoneal shunt (VPS) devices. This technique dislodges biofilm bacteria from the surface of implanted materials before culture. Removed devices were sonicated in saline (40 kHz, 1 minute, 0.25 W/cm²), the resulting fluid was cultured aerobically and anaerobically at 37 °C, and bacterial growth was counted. Ventricular cerebrospinal fluid (CSF) was cultured separately. In the EVD group, sonication cultures grew significantly more bacteria (64%, 9/14) than cultures of aspirated ventricular CSF (14%, 2/14). In the VPS group the difference was not significant. Positive sonication cultures of EVD catheters yielded a median of >100 colony forming units (CFU) (range, 60–800). For positive sonication cultures of VPS, the median was 1000 CFU (range, 20–100,000). All patients with bacteria in their CSF also had positive sonication cultures from the removed device. Of the five patients with sterile or presumably contaminated CSF cultures but positive sonication cultures of removed shunts, one became afebrile after removal of the EVD, two developed meningitis and two remained asymptomatic. Sonication culture of EVD appears to improve the microbiological assessment of device-related infection and it corroborates with CSF cultures of revision surgery for VPS. Sonication of the removed EVD tip may raise awareness for the onset of meningitis.     

Risk Factors Associated with Infections and Need for Permanent Cerebrospinal Fluid Diversion in Pediatric Intensive Care Patients with Externalized Ventricular Drains

Background

Externalized ventricular drains (EVDs) are commonly used in pediatric intensive care units (PICU) but few data are available regarding infection rates, infection risks, or factors associated with conversion to permanent cerebrospinal fluid (CSF) diversion.

Methods

Retrospective observational study of patients managed with EVDs admitted to a tertiary care PICU from January 2005 to December 2009.

Results

Three hundred eighty patients were identified. Neurologic diagnostic groups were externalization of existing shunt in 196 patients (52 %), brain tumor in 122 patients (32 %), intracranial hemorrhage in 23 patients (6 %), traumatic brain injury in 17 patients (5 %), meningitis in 9 patients (2 %), or other in 13 patients (3 %). Six percent of all patients (24/380) had new infections associated with EVD management for an infection rate of 8.6 per 1,000 catheter days. The median time to positive cultures was 7 days (interquartile range 4.75, 9) after EVD placement. Patients with EVD infections had significantly longer EVD duration 6 versus 11.5 days (p = 0.0001), and higher maximum EVD outputs 1.9 versus 1.5 mL/kg/h (p = 0.0017). Need for permanent CSF diversion was associated with higher maximum EVD drainage (1.3 vs. 1.6 mL/kg/h p < 0.0001), longer EVD duration (5 vs. 4 days, p < 0.005), and younger age (4.5 vs. 8 years, p < 0.02) but not intracranial hypertension (72 vs. 82 % of patients, p = 0.4).

Conclusions

In our large pediatric cohort, EVD infections were associated with longer EVD duration and higher maximum EVD output. Permanent CSF diversion was more likely in patients with higher maximum EVD drainage, longer EVD duration, and younger age.     

大剂量尿激酶注入脑室治疗重度原发性脑室出血的效果

目的探讨大剂量尿激酶注入脑室治疗重度原发性脑室出血的效果。方法将65例重度原发性脑室出血患者随机分为治疗组(33例)与对照组(32例)。两组均采用双侧脑室穿刺置管引流,治疗组患者每天侧脑室注入尿激酶10万IU,对照组患者侧脑室注入尿激酶2万IU,连续3~7 d。两组患者在侧脑室引流管拔除后均行腰大池置管引流。治疗后每天行头颅CT检查,观察脑室血肿的变化;并观察颅内感染、脑积水发生的状况。结果治疗组脑室血肿消失及侧脑室、腰大池置管引流时间均明显短于对照组(均P0.01)。治疗组无1例出现脑积水及颅内感染,对照组出现脑积水7例(21.8%)、颅内感染8例(25.0%),两组比较,差异有统计学意义(均P0.01)。结论大剂量尿激酶注入脑室治疗重度原发性脑室出血有显著效果,可迅速清除脑室积血,缩短脑室、腰大池置管引流时间,减少颅内感染和脑积水等并发症。     

Comparison of ventricular drainage in poor grade patients after intracranial hemorrhage

Abstract

Objectives: The selection of patients and treatment criteria for acute hydrocephalus and intracranial pressure (ICP) after intracranial hemorrhage remains unclear. In general neurosurgical practice, there is a tendency to use external ventricular drainage (EVD) for the patients. This study was undertaken to analyse the complications and efficiency of the different treatment modalities.

Methods: The effects, complications and outcome of ventricular drainage on high ICP and hydrocephalus were analysed retrospectively in 109 patients with intracranial hemorrhage. All the patients were assessed using the Glasgow Coma Scale, computed tomography and ICP monitoring. We excluded patients over the GCS of 8. All patients underwent a procedure for ICP monitoring plus ventricular cerebrospinal fluid (CSF) drainage. Sixty-one patients were managed with one (single) EVD system; 12 patients needed two EVD systems consecutively, while 23 patients underwent an EVD procedure followed by permanent ventriculoperitoneal (VP) shunt insertion. Thirteen patients were treated only by VP shunt for ventricular drainage. The infection rate and outcome 9 months after hemorrhage were analysed.

Results: The infection rates were 8.1% in the one-EVD group, 33.3% in the two-EVD group (one EVD versus two EVD, p<0.05), 8.6% in the EVD-VP group and 7.7% in the VP shunt group. The mortality rates were 73.7% in the one-EVD group, 83.8% in the two-EVD group, 47.8% (p<0.05) in the EVD-VP group and 53.8% (p<0.01) in the VP shunt group.

Discussion: This study indicates that single and short-term use of EVD and/or early VP shunting are associated with a low risk of infection. Furthermore, early VP shunting may protect the brain from the irregular control of intracranial hypertension and may allow more time for resolution of CSF circulation and significantly lowers the mortality rates.     

Ommaya囊联合侧脑室外引流治疗脑室内出血

目的探讨脑室内出血(IVH)的治疗方法并评价其临床疗效。方法 40例IVH病例随机分为改良组及传统组。改良组选择在出血相对较多的一侧常规行侧脑室额角穿刺外引流;而在出血相对较少的一侧额角置入Ommaya囊后行囊腔穿刺外引流。脑室外引流5~7 d后,改为仅Ommaya囊穿刺外引流。传统组则行双侧侧脑室普通外引流,5~7 d后结合腰大池置管持续引流血性脑脊液治疗。比较两组患者迟发性脑积水、颅内感染发生率及预后情况等。结果两组迟发性脑积水、颅内感染发生率及预后(ADL分级)比较差异有统计学意义(P0.05),表明改良组疗效明显优于传统组。结论该项改良技术安全可靠、损伤小、恢复快,能大大降低病死率和伤残率,减少并发症和后遗症,改善预后,优于传统方法。     

Surgical management of posthemorrhagic hydrocephalus in 22 low-birth-weight infants

In order to assess the complication rates of cerebrospinal fluid diversion techniques used at our institution, a retrospective study of the surgical management of posthemorrhagic hydrocephalus was conducted from a population of 547 premature infants admitted to the neonatal intensive care unit from 1987 to 1989. The incidences of periventricular-intraventricular hemorrhage in the 3 years studied were 44%, 37%, and 27%, respectively. Thirty-nine of the infants developed posthemorrhagic hydrocephalus as determined by serial cranial ultrasonography; 22 required cerebrospinal fluid diversion. During the study period, we began using subcutaneous ventricular reservoirs and a low-pressure Neonatal Shunt (customized device) in infants weighing less than 1500 g at the time of instrumentation. This change in management was associated with a significant reduction (P<0.005) in the morbidity and mortality compared to the use of external ventricular drainage devices. On the basis of these findings, the use of external ventricular drainage devices was discontinued.     

长程皮下通道脑室外引流技术在重型颅脑损伤术后泛耐药鲍曼不动杆菌颅内感染治疗中的应用研究

目的探讨长程皮下通道脑室外引流(LTEVD)技术在治疗重型颅脑损伤(TBI)术后泛耐药鲍曼不动杆菌(XDR-AB)颅内感染的临床效果。方法回顾性分析2014年1月1日-2018年12月31日中南大学湘雅医院收治的65例TBI开颅术后并发颅内感染患者的临床资料。其中,50例以短程皮下通道脑室外引流(STEVD)技术治疗为STEVD组,15例术后并发XDR-AB性颅内感染行LTEVD技术治疗为LTEVD组。所有患者均进行围手术期规范化管理,依据脑脊液细菌培养药敏结果选择敏感抗生素治疗,XDR-AB者同期予以脑室内多黏菌素给药。结果两组患者一般特征、脑积水发生率、新增感染率及病死率比较,差异均无统计学意义(P>0.05)。STEVD组脑室内置管时间为(10.7±5.3)d,中位数10.0 d。而LTEVD组脑室内留置导管时间为(31.7±9.2)d,中位数32.0 d。两组比较,差异有统计学意义(P <0.05)。结论 LTEVD技术可以安全地延长脑室外引流时间超过1个月,疗效好,适用于难治性颅内感染或颅内外顽固性积液需长时程(>4周)脑脊液引流患者。     

微创开颅四脑室血肿清除联合脑室外引流治疗重型脑室出血临床观察

目的探讨微创开颅四脑室血肿清除联合脑室外引流治疗重型脑室出血的临床疗效。方法筛选2016-01—2018-01新乡市中心医院收治的58例自发性重型脑室出血患者,随机分为开颅组(行微创开颅四脑室血肿清除联合脑室外引流术)和对照组(单纯行双侧脑室外引流术)各29例。比较2组患者术前与术后24 h GCS评分、术后3 d脑室内血肿清除率、脑室引流管带管时间、术后并发症(再出血、颅内感染、脑积水)发生率、术后6个月存活患者日常生活能力(ADL)评分。结果开颅组患者术前与术后24 h GCS评分比较,差异有统计学意义(P<0.05);开颅组术后3 d脑室内血肿清除率、脑室引流管带管时间、术后并发症发生率及术后6个月存活患者ADL评分与对照组比较,差异均有统计学意义(P<0.05),开颅组治疗效果优于对照组。结论采用微创开颅四脑室血肿清除联合脑室外引流术治疗重型脑室出血,能明显改善患者预后。     

Moving the goalposts: A comparison of different definitions for primary external ventricular drain infection and its risk factors: A multi-center study of 2575 patients

External ventricular drainage is the most common procedure performed in daily neurosurgical practice. One devastating complication is ventriculostomy-associated infection, but the establishment of evidence-based management guidelines has been hindered by the lack of an universal definition. There is also limited data with regard to the utility of comorbidity health indices and surgery-related factors in predicting infection. This study aims to compare the incidence of infection according to five commonly used definitions and to identify risk factors for this complication. 2575 patients from seven neurosurgical centers in Hong Kong underwent primary external ventricular drainage. The frequency of infection according to Gozal was 2.2% (n = 57), 4.7% (Chi), 0.6% (Lozier), 0.8% (Lyke) and 2.8% (Scheithauer). The commonest pathogen was coagulase negative staphylococcus (39%) and 49% of all microbial isolates were multiple-drug resistant. The mean Charlson comorbidity index was 0.5 ± 1.1. Using Gozal’s definition as the primary endpoint, the index was not predictive of infection and no surgical risk factors were identified. The only significant risk factor was the performance of two or more additional neurosurgical procedures within 30 days of catheterization (OR: 2.1, 95% CI 1.1–4.5). The rate of infection is relatively low, but considerable disparity exists depending on the definition used. Our data implies that patient factors, in particular the Charlson comorbidity index, and variations in surgical practice are less influential than the strict observance of infection control measures. The high incidence of antibiotic-resistant bacteria is concerning and the routine of exchange of catheters within 30 days should be discouraged.     

脑积水合并颅内感染的治疗策略

目的探讨脑积水合并颅内感染的治疗策略。 方法选择自陆军总医院附属八一脑科医院2011年1月至2014年8月18例脑积水合并颅内感染的病例,其中15例需要行脑脊液外引流术,3例间断行腰椎穿刺控制颅内压,10例轻中度感染者只予以单纯静脉抗感染治疗,8例感染较重者应用鞘内注射抗生素+静脉抗感染联合治疗。感染控制后6例行内镜第三脑室底造瘘术,11例行分流手术,1例放弃治疗,比较内镜治疗组及分流治疗组间感染控制的天数、二重感染发生率及总体并发症发生率,利用SPSS 16.0统计分析软件对资料进行统计。 结果感染控制后6例行内镜第三脑室底造瘘术,11例行分流手术,1例放弃治疗,内镜治疗组感染控制的天数平均（14.6±1.7）d,二重感染率为0,术后并发症发生率为33.33%,分流治疗组感染控制的天数平均（22.3±3.4）d,二重感染率为18.2%,术后并发症发生率为45.45%。内镜治疗组及分流治疗组间感染控制的天数及二重感染率有明显差异（P<0.05）,而术后并发症总发生率没有明显差异（P>0.05）。 结论脑积水合并颅内感染治疗难度大,并发症多,在控制感染、避免二重感染发生率方面内镜手术较分流手术有优势,内镜手术应作为脑积水合并颅内感染的首选治疗方法。