Eur Radiol (2004) 14:227–233 DOI 10.1007/s00330-003-2134-y

M. Krötz U. Linsenmaier K. G. Kanz K. J. Pfeifer W. Mutschler M. Reiser

Received: 29 January 2003 Revised: 7 July 2003 Accepted: 1 October 2003 Published online: 6 November 2003 © Springer-Verlag 2003

M. Krötz (✉) · U. Linsenmaier K. J. Pfeifer · M. Reiser Department of Clinical Radiology, Klinikum der Ludwigs-MaximiliansUniversität - Innenstadt, Nussbaumstrasse 20, 80336 Munich, Germany e-mail: [email protected] Tel.: +49-89-51609200 Fax: +49-89-51609292 K. G. Kanz · W. Mutschler Department of Surgery, Klinikum der Ludwigs-MaximiliansUniversität - Innenstadt, Nussbaumstrasse 20, 80336 Munich, Germany

NEURO

Evaluation of minimally invasive percutaneous CT-controlled ventriculostomy in patients with severe head trauma

Abstract Evaluation of percutaneous CT-controlled ventriculostomy (PCV) in patients with severe traumatic brain injury to measure intracranial pressure as a component of early clinical care. A consecutive series of 52 interventions with PCV was prospectively analyzed with regard to technical success, procedural time, time from the initial cranial computed tomography (CCT) until procedure and transfer to the intensive care unit (ICU). Additionally, the data was compared with a retrospective control group of 12 patients with 13 procedures of conventional burr-hole ventriculostomy (OP-ICP). The PCV was successful in all cases (52 of 52; 95% CI 94–100%). In 1 case a minor hemorrhage into the ipsilateral lateral ventricle was observed on CT scans due to an initially unsuccessful puncture (95% CI 0–6%). No infections occurred (95% CI 0–6%). In the control group with OP-ICP one catheter infection

Introduction Monitoring of intracranial pressure using an intracranial ventricular drainage catheter (ICP catheter) is an established technique during the treatment of severe traumatic brain injury [1, 2, 3, 4, 5, 6, 7, 8]. Such ventricular catheters allow for a continuous registration of intracranial pressure for diagnostic purposes and offer the possibility of drainage of cerebrospinal (CSF) fluid for therapy of intracranial pressure and the cerebral oedema associated with it. For positioning of ICP catheters flexible cathe-

and one unsuccessful catheter placement occurred (each 8%, 95% CI 0–20%). The PCV led to a significant decrease of procedure time from 45±11 min (OP-ICP) to 20±12 min (PCV). The interval from the initial CCT until procedure (PCV 28±11 min, OP-ICP 78±33 min) and transfer to the ICU (PCV 69±34 min, OP-ICP 138±34 min) could also be significantly reduced (each with p<0.05, Mann-Whitney U-test). Percutaneous CT-controlled ventriculostomy is a safe and efficient method for ICP catheter placement during initial trauma room management. It significantly reduces the time of initial trauma room treatment. Keywords Intracranial pressure · Computed tomography · CT-controlled ventriculostomy · Ventricular catheters · Traumatic brain injury · Craniocerebral trauma · Multiple trauma

ters of 3 mm in diameter consisting of soft polymers are used [9, 10]. Up to now ICP catheters where placed either in the operating room, on the intensive care unit (ICU) or in the trauma room following drilled skull trepanation in an unguided manner, which means without the use of supporting imaging techniques during the procedure. Following the implantation and after the transport of the patient to the radiology department, the control of correct positioning of the ICP catheter was performed by cranial computed tomography (CCT). In the case of mispositioning of the ICP catheter device a renewed trans-

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port of the patient to the operating room for revision was necessary with subsequent renewed transport for control by CCT. Percutaneous CT-controlled ventricular catheter placement (PCV) offers an alternative to this procedure. During PCV the ventricular catheter is implanted under CT-guidance during the procedure within the CT examination room. The patient remains on the CT tray for the complete duration of the procedure [10, 11]. The decisive advantage of PCV is the possibility of immediate imaging, which allows for quick correction of the ICP catheter in case of mispositioning. The time factor plays a crucial role in the initial care for multiple injured patients in the trauma room [12, 13]; therefore, the time until a patient can be transferred to the ICU or the operating room after initial care within the trauma room may not be extended due to CT-ICP. In a surgical feasibility study from this institution [10] conventional burr-hole ventriculostomy was compared with percutaneous CT-controlled ventriculostomy. It was the objective of this study to analyse data of a large prospective patient cohort that received percutaneous CTcontrolled ventricular catheter placement with special respect to technical feasibility and to the time needed. Furthermore, the technique of percutaneous CT-controlled ventricular catheter placement is presented as an interventional radiological procedure, performed by interventional radiologists and neurological trained surgeons. In addition, patients who received PCV were compared with a group of control patients that received conventional drilled ventriculostomy.

Materials and methods We prospectively analysed 50 consecutive patients that received a total of 52 percutaneous CT-controlled ventricular catheter placements (PCV). Indication for PCV was set according to the recommendations of the American Association of Neurological Surgeons (AANS) of 1995–1996 (Table 1) [1]. Data were analysed with respect to technical success and to the amount of appearing complications. The times needed for PCV and the transfer times from the beginning of the diagnostic CCT until to the transport of the patient to the ICU were recorded. Documentation of data was performed according to the protocol for multiple injured patients of the German Society of Trauma Surgeons (DGU) which is routinely evaluated in our hospital [14]. In this trauma-protocol the trauma mechanism, the degree of injury (GCS), all clinical and radiologic diagnosis and the time needed for all diagnostic and therapeutic procedures are recorded in a continuous manner. The written report of the digitally archived CT

scans were reevaluated retrospectively. In addition, data were compared retrospectively to a historic control group from 12 patients of our hospital who received a total of 13 treatments in which a surgically drilled skull trepanation with ICP catheter placement (OP-ICP) was performed [10]. Data of patients receiving PCV were collected from August 1998 to February 2000. Data of patients receiving OP-ICP were collected from July 1993 to April 1996. Mean age in the PCV group was 46±17 years, within the OP-ICP group it was 42±19 years. PCV catheter placement After obtaining a diagnostic CCT of the neurocranium (spiral CT, skull base 2/2/4 mm, neurocranium 8/8/8 mm, advance/scan thickness/reconstruction increment, respectively; Somatom Plus 4, Siemens, Medizinische Technik, Erlangen, Germany) within the trauma-room treatment the indication for ICP catheter placement was set. To prepare ICP catheter placement the patient on the CT tray was driven out of the CT gantry head first. Special care was taken for fixing the patient head in the exact same position as during performance of the diagnostic CCT. It had to be assured that the operator had free vision and access to the external acoustic meatus as these are important points during catheter insertion (see below). Free vision and access to the parietal skull was also assured. Placement was performed under intubation anaesthesia, the tubes of the respiration automat were let to the head of the patient from caudal to cranial through the CT gantry. The CT gantry was covered with self-adhesive sterile surgery cloth, the operating room light was positioned and covered with a sterile hand grip. After shaving a minimum of an 8¥8-cm wide area parietal of the designated side of intervention the position of the puncture was marked: Under normal conditions this is 11 cm cranial of the nasal root and 2–3 cm lateral of the sagittal line. In addition, for marking the designated position of puncture the diagnostic CCT scan was double checked. Following disinfections, the operating area was covered with a large self-adhesive transparent plastic cloth to guarantee free vision of the operator to the landmarks (external acoustic meatus and nasal root). After scalpel incision of the skin, a drilled hole of 3 mm diameter was set at the marked position using a hand driller. During this the tabula externa and interna, and under great caution, the dura mater were penetrated. In performing this procedure, it had to be assured that from the very beginning of drilling the designated direction of catheter insertion had been followed, as the channel of drilling would be used as guidance for the catheter. In case of nonectopic lateral ventricles a virtual target of a crossing of a line that connects both external acoustic meati and a line from the drilling hole towards the medial angle of the contralateral eye was taken. Prior estimation of the respective angle according to the initial diagnostic CCT scan was performed and is recommended. After this, the ICP catheter measuring 3 mm in diameter consisting of the guide wire and the flexible polymer catheter was implanted. It was first advanced for 6 cm into the direction of the virtual target crossing. When crossing the ependyma of the ventricle a weak resistance could typically be felt by the operator. In case of correct catheter positioning and increased intracranial pressure the removal of the guide wire is immediately associated with spontaneous

Table 1 Indications for ventricular catheter placement according to the recommendations of the American Association of Neurological Surgeons [1]. TBI traumatic brain injury, GCS Glasgow coma scale Severe TBI with initial GCS <9 and pathological CCT findings (oedema, intracerebral bleeding, subarachnoid bleeding, sub- or epidural haematoma) Severe TBI with initial GCS <9 and normal CCT if ≥2 of the following criteria are applied: age >40 years, RR systolic <90 mmHg, uni- or bilateral motor posturing TBI with initial GCS=9–13 and ICU stay with respiration ≥24 h

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Table 2 Indications for ventricular catheter placement of the study group. Because of combined injuries, there are one or more entries per patient possible. PCV percutaneous CT-controlled ventriculostomy. OP-ICP conventional burr-hole ventriculostomy

Generalized oedema Isolated or multiple intracerebral bleedings Posttraumatic subarachnoid bleeding Small subdural haematoma Small epidural haematoma Intensive care unit >24 h Revision by dislocation

Fig. 1 Percutaneous CT-controlled ventricular catheter implantation (PCV). The patient is moved out of the CT gantry head first. The head of the patient is covered with a self adhesive plastic cloth. The position of the puncture was marked before the beginning of the intervention. For improved orientation during the puncture the surgeon is marking the left acoustic meatus with his left index finger release of clear CSF fluid from the catheter. Before fixing the catheter on skin level, the correct positioning was controlled by a CCT scan. For this the patient was driven back into the gantry and an axial spiral CT of the neurocranium was performed (Spiral CT; 8/8 mm advance/level thickness, respectively; Somatom Plus 4, Siemens, Erlangen, Germany). In case of an incorrect positioning of the catheter outside of the ipsilateral ventricle the revision of the catheter could be planed according to the control CCT after renewed removal of the patient out of the CT gantry. In this study the correction of such mispositioning of the ICP catheter was counted as renewed puncture. In case of correct positioning of the catheter according to the control CCT the catheter was fixed on skin level and the procedure was completed using a sterile wound dressing (Fig. 1). Statistics Results are given as mean±standard deviation. Confidence intervals for technical success were calculated within groups. Qualitative variables were compared between groups using the Fischer’s exact test. Quantitative variables were compared between groups using the Mann-Whitney U test. A p value £0.05 within a confidence interval of 95% was taken as statistically significant.

Results In the PCV group 52 ventricular catheters were implanted in 50 patients: In 2 cases a revision of the catheter had to be performed 3 days after the initial placement due to a catheter dislocation at the ICU. In the OP-ICP group 13 surgeries were performed in 12 patients: one patient within this group suffered from contamination of the catheter 4 days after being transferred to the ICU, showing clinical signs of a ventriculitis with local skin rash

PCV

OP-ICP

21 23 16 10 4 5 2

– 7 2 3 1 – –

but no laboratory signs of sepsis and with spontaneous healing following immediate removal of the catheter. Thirty-nine (78%) of the patients in the PCV group and 8 (67%) patients in the OP-ICP group developed increased intracranial pressure 1–3 days following the trauma. Eight (16%) patients within the PCV group and 1 (8%) patient within the OP-ICP group had to undergo surgical trepanation of the skull for relief from increased intracranial pressure due to subdural (in 2 patients of the PCV group) or epidural (in 1 patient of the PCV group) haematoma, increasing intracerebral bleeding due to contusion or increasing generalized cerebral oedema. Indications for the ICP catheter placement within both groups were set according to the criteria of the AANS [1] and are outlined in Table 2. Notably in both groups the total amount of indications is larger than the total amount of the patients per group which is due to selective counting of different injuries as selective indications in cases of combined trauma. The Glasgow Coma Scale (GCS) within the PCV group had a range from 6 to 8 at the time of admission; within the OP-ICP group it was below 9 (Table 2). Technical success Percutaneous CT-controlled ventriculostomy (PCV) was successful in all of the 52 cases (95% CI 94–100%). There was no misplacement. In 1 patient a bleeding into the ipsilateral side ventricle developed due to an unsuccessful initial puncture (95% CI 0–6%). This bleeding remained free of symptoms throughout the clinical course. No infections occurred within the PCV group (95 CI 0–6%). In the control group (OP-ICP group) there was one misplacement and one infection of the catheter after 4 days (each 7.7%; 95% CI 0–22%). There were no statistically significant differences between the PCV or the OP-ICP group, probably due to the low case count in the OP-ICP group (Table 3). In the PCV group there was a mean of 1.3 attempts of puncture in each patient leading to successful placement of the catheter. Especially in those patients with com-

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Fig. 2a, b Complicated PCV of a patient with diffuse cerebral oedema, massive midline shift to the left side and subtotal compression of the left side ventricle. a At the initial cranial computed tomography (CCT) a slightly lateral catheter displacement was diagnosed. Clinically, the catheter was not recurrent after this initial puncture. b After CT-controlled replacement, a correct catheter position could be achieved and the catheter was recurrent

Fig. 3a, b The PCV of a patient with an intracerebral bleeding within the left frontal lobe. a The initial CCT shows an intraparenchymateous misplacement of the catheter lateral to the left side ventricle. b The CCT after CT-controlled catheter revision shows a correct position of the catheter within the left side ventricle

Table 3 Technical success and complications of both groups

Misplacement 95% CI Infection 95% CI Bleeding 95% CI

PCV (%)

OP-ICP (%)

p value

0 of 52 (0) 0–6 0 of 52 (0) 0–6 1 of 52 (2) 0–6

1 of 13 (8) 0–22% 1 of 13 (8) 0–22% 0 of 13 (0) 0–23

0.424 – 0.424 – 0.254 –

due to the continuous presence of the possibility to take CT scans (Figs. 2, 3). In the control group there was a mean of 1.5 attempts at puncture for successful placement of the catheter. In 1 case successful placement of the catheter using OP-ICP was not successful despite six attempts at puncture. This operation was unsuccessfully finished. Time needed

pressed or heavily displaced side ventricles there was a need for an increased number of attempts of puncture. Particularly in those patients the percutaneous CT-controlled ventricular catheter placement allowed reliable placement of the ICP-catheter in the ipsilateral ventricle

In both groups time spent from the beginning of the skin disinfections until placement of the sterile wound closure was assessed. Percutaneous CT-controlled ventricular catheter placement (PCV), despite expensive desinfections measures before beginning the puncture, succeeded

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Table 4 Time needed for intervention and transfer of both groups

Time of intervention Initial CCT until intervention Initial CCT until transfer

PCV (min)

OP-ICP (min)

p value

20±12 28±11 69±34

45±11 78±33 138±34

<0.05 <0.05 <0.05

in reducing the time of the intervention with the mean of 25 min. The time spent for PCV counted from preparation of the patient until fixation of the ICP-catheter and sterile wound closure amounted 20±12 min, in the control group (OP-ICP) the intervention took a mean of 45±11 min. The PCV decreased time spent from the initial diagnostic CCT until the beginning of the intervention and from the beginning of the initial diagnostic CCT until transferal of the patient to the ICU significantly (Table 4).

Discussion Patients suffering from traumatic brain injury with an initial Glasgow Coma Scale below 9 and a pathological CCT diagnostic scan have an increased risk of developing a pathologically high intracranial pressure [4, 5, 7, 8]. For this reason the AANS recommends continuous monitoring of intracranial pressure in these patients [1]. By continuous measurement of the intracranial pressure during intensive care the cerebral perfusion pressure can be calculated. Increase of intracranial pressure above 20–25 mm Hg brings about the risk of decrease cerebral perfusion and of an upper transtentorial squeezing [1, 2, 3, 4, 5, 6, 7, 8, 15]. Continuous monitoring of intracranial pressure during intensive care succeeded in lowering the mortality of heavy traumatic brain injury (Glasgow Coma Scale below 9) from 50–54% to 12–36% [1, 2, 4, 16, 17]. Invasively implanted ventricular catheters as well as intraparenchymatous and epidural pressure-release systems allow for reliable assessment of intracranial pressure [1, 18, 19, 20, 21, 22]. In general, ventricular catheters are implanted performing a drilling ventriculostomy at the OR or at the ICU. This intervention is usually performed without the use of imaging techniques. The catheter is positioned blind and the surgery is counted as successful as soon as CSF fluid drains out of the catheter. Following the intervention and before transferal to the ICU the patient is usually transported to the radiology department for CCT control of the catheter position. In case of mispositioning of the catheter there is a surgical revision followed by a renewed transport of the patient to the operating room, a renewed sterile procedure and another postoperative transport of the patient for CT diagnostics.

An advantage of such invasively placed ventricular catheters which, in comparison with intraparenchymatous or epidural systems, are more invasive, is the possibility of draining CSF fluid to relieve intracranial pressure beside measuring intracranial pressure; however, the system being open during drainage it will not allow for intracranial pressure monitoring concomitantly. Other problems of ventricular catheters are mismeasurements in case of the transducer being incorrectly mounted not on the same level as the side ventricle or a disturbance of liquid flow towards the transducer in case of compressed side ventricles. In contrast to these intraventricular catheters, the less invasively positioned intraparenchymatous pressure–release systems allow for a more reliable assessment of intracranial pressure without the possibility of direct influence on intracranial pressure due to CSF fluid drainage [1, 18, 19, 20, 21, 22]. In this study the method of percutaneous CT-controlled ventricular catheter placement (PCV) was used which offers a number of advantages compared with surgical drilling ventriculostomy. Despite the more invasive placement procedure when compared with alternative pressure-monitoring devices, it allows for correct placement and does minimize the cerebral parenchymatous damage caused by the intervention. In all patients treated the implantation of the catheter was successful. Only in 1 case was there a mild haemodynamically irrelevant bleeding into the ipsilateral side ventricle. This bleeding was fully resorbed during the clinical course and did not lead to any symptoms during the patients’ stay on ward. The infection rates associated with the implantation of intracranial ventricular catheters and intraparenchymatous pressure-monitoring devices amounts to up to 0–27% of patients depending on the author of the study [5, 23, 24]. In this study 1 patient of the control group (OP-ICP) developed ventriculitis 4 days following the implantation of the catheter (7.7%). Immediate removal of the catheter led to complete reconstitution. Considering a 95% confidence interval of 0–6% for the PCV group and of 0–22% for the OP-ICP group, the results of this study match the results published thus far with respect to the frequency of infections during ventricular catheter placement [5, 23, 24]. In contrast to the OP-ICP group, catheter placement within the PCV group was successful in all cases, and due to the extensive disinfection measures taken before the intervention, there were no periprocedural infections. Nevertheless, the PCV placement performed during trauma room CT scanning cannot match the optimized conditions of an operating room with regard to sterile surroundings. Also in this study with a relatively high number of 52 interventions for the PCV group infections of the catheter may occur in up to 6% of cases with a 95% probability. There is no significant difference between the PCV group and the control group (OP-ICP) concerning periprocedural infections and bleeding. This, however, might

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be due to the low number of cases in the control group. In the literature periprocedural infection rates of 0–10.4% and relevant bleeding complication rates of 0.5% are indicative for surgical drilling trepanation (OP-ICP) [3, 9, 20, 25, 26, 27, 28, 29]. A shortcoming of the presented study is the comparison of a prospective study group (PCV) vs a retrospective control group (OP-ICP). Since the introduction of CT-controlled ICP catheter placement at the authors’ institution, conventional burr-hole ventriculostomy is no longer performed. Because of that, we used patients who had received conventional burr-hole ventriculostomy at the authors’ institution until 1996 as a retrospective, historical control group. Because CT is performed immediately after ventricular puncture, and before fixation of the catheter its position can be controlled immediately and in case of mispositioning the necessary revision can be planed according to the CT images. For this, the operator needs an undisturbed view towards a CT monitor mounted on the ceiling of the CT room during catheter revision to give an image of the CT scan [11, 30]. Strict caution was taken to avoid changing of the tilting of the gantry and the head during the intervention in case of repeated puncture, so the operator was guaranteed a reliable orientation. This proceeding during PCV with immediate postinterventional imaging proofs to be especially helpful in case of difficult conditions of puncture as presented by dislocated or compressed side ventricles (Figs. 2, 3). For performance of PCV the equipment within the CT room is of special importance [30, 31]. There is an imperative need for a CT monitor within the CT room which can be observed from the headward side of the gantry and allows for double checking the control scan during ICP catheter placement. There should also be an operation lamp on the headward side of the CT scanner. On planning the CT examination room there should be enough space on this headside for an operator, an operating room nurse and the tables for instruments; therefore, there should be at least 2 m of space in extension of the CT table on the cranial part [30, 31]. As this is not the case in most trauma centers thus far, this should be respected when furnishing trauma rooms in the future. A further development of the presented method may be achieved using CT fluoroscopy [11]. The CT fluoroscopy allows for continuous X-ray scanning during ICP catheter placement within the CT gantry. Using a singledetector CT scanner, only the level of the ventricles can be visualized and the insertion channel cannot be visualized throughout its continuity. The introduction of multidetector spiral CT scanners (MSCT) with an increased number of detector rows and the ability to cover a larger layer volume may allow for visualization of the complete insertion channels continuity. The addition of a navigatory unit may provide another improvement of the method. Whether the increase in technical and timely effort will

prove to be acceptable in an emergency situation is a subject of further clinical testing. A highly important advantage of PCV compared with OP-ICP are the statistically significant time savings: firstly, the time for the intervention itself could be halved by PCV in comparison with OP-ICP. As PCV catheter placement could be performed during initial trauma room treatment, it could be performed immediately after stabilizing the patient by the anaesthesist and after performing a diagnostic CCT on the CT tray. By doing this, the period between diagnostic and intervention could be reduced from 78±33 min in OP-ICP to 28±11 min in PCV. All together, the procedural and periprocedural time savings succeeded in significantly reducing the time needed from trauma room treatment until transfer of the patient to the ICU or the OR. But the time saved in our center by application of this method cannot be simply transferred to other hospitals. In our trauma center there is no spatial division of the radiology department, the operating room and the ICU. The CT in the trauma room is on the ground floor with direct exit to an elevator. The operating room and the ICU are on the first floor approximately 10 m in distance of the elevator. This fact even emphasizes the timely effectiveness of PCV during trauma room treatment as even in those low distances the observed savings in intervention time and periprocedural time could be realized; therefore, in hospitals were the spatial division of departments is larger than in our institution, the method is likely to achieve an even larger time savings.

Conclusion Percutaneous CT-controlled ventriculostomy (PCV) is a safe and feasible technique for monitoring and therapy of intracranial pressure during trauma room care. Because of the immediate access to imaging techniques, it allows for safe placement of the ventricular catheter even in challenging situations of compressed side ventricles or in the case of laterally dislocated ventricles due to unilateral cranial pressure. In our centre, despite already optimized conditions of short distances between trauma room/CT, operating room and ICU, PCV catheter placement leads to a clear, statistically significant time savings.

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