Percutaneous construction of ventriculo-atrial (VA) shunt – Case report

Abstract

Introduction and importance

The commonest method of elective CSF diversion remains ventriculo-peritoneal shunt (VP shunt). But in some circumstances, VP shunts fail repeatedly or becomes unattractive to the neurosurgeon and this calls for exploration of alternatives. For the index case, Ventriculo-atrial (VA) shunt was favoured and the objective in this report is to share experience gathered there from. Learning points serve to highlight the use of VA shunts as a resort in the drainage of cerebrospinal fluid in the case of repeated failures of peritoneal diversion of CSF and to explain our explain our experience with this index case.

Case presentation

A 54 years old obese woman with previous history of total abdominal hysterectomy was reported. She underwent repeated (three times) revisions of failed peritoneal end of her VP shunt on a background of obstructive hydrocephalus secondary to a posterior fossa tumour (previously excised). Following repeated failure of peritoneal catheter function, she underwent VA shunt and did well.

Clinical discussion

The decision to place a VA shunt was made after careful deliberations. We discuss the peculiarities in placing a VA shunt. Following placement of a VA shunt, improvement was noted in her clinical condition at one week post op and has been sustained at multiple follow up clinic visits.

Conclusion

VA shunts become an option for cerebrospinal fluid drainage when it becomes unequivocally clear in a multidisciplinary setting that the peritoneal catheter is unlikely to work in view of the unfavourable circumstances of the peritoneal cavity.

Highlights

• •Female who previously had a total abdominal hysterectomy presented with progressive loss of balance and difficulty in walking with dizziness, generalized weakness and slurring of speech.
• •NCCT Brain scan revealed a pan ventriculomegaly with a marked dilatation of the 4th ventricle suggesting impaired drainage.
• •Multiple revisions of the peritoneal catheter did not help with draining CSF
• •A VA shunt was chosen as a resort.
• •VA shunts are indispensable options for cerebrospinal fluid drainage in hydrocephalus.

1. Introduction

There are quite a few options for continuous cerebrospinal fluid (CSF) drainage including ventriculo-peritoneal (VP) shunts, ventriculo-pleural shunts, endoscopic third ventriculostomy, ventriculo-atrial (VA) shunts etc. Ventriculo-peritoneal (VP) shunts are commoner but may occasionally fail and revisions may be required for several reasons including shunt infection, obstruction, and migration etc. [1]. In such special events, ventriculo-atrial (VA) shunts may be an appropriate option for continuous cerebrospinal fluid drainage [2]. If VA is selected, accurate pre-operative planning, intra-operative vein selection and exact shunt placement is important to guarantee free drainage, reduce complications such as kinking and obstruction [3]. Placement strategies and monitoring methods have been improved to achieve more success in VA shunt construction [4]. This procedure was carried out in a tertiary private practice setting.

2. Method

In this case review, reasons, protocols, and immediate clinical and neurological outcomes of VA shunt placement was reported. This work has been reported in line with the SCARE criteria [5].

3. Case report

A 54 years old, high BMI female with previous midline sub-umbilical scar for total abdominal hysterectomy presented with progressive loss of balance and difficulty in walking associated with dizziness, generalized weakness and slurring of speech all of four weeks. She had an obstructive posterior fossa cystic mass lesion which was removed via a sub-occipital craniotomy seven months earlier but four months prior to that a VP shunt was constructed to first manage the obstructive hydrocephalus. There was no significant medication history, family history or psychosocial history.

Neurological examination on the latter presentation revealed drowsy, lethargic rather confused middle aged woman, GCS 14/15, Pupils 3 mm bilaterally and sluggish reaction. VP shunt valve refilled satisfactorily upon gentle pressing. A quick NCCT Brain scan revealed pan-ventriculomegaly with a marked dilatation of the 4th ventricle suggesting impaired drainage from its outlets (Magendie and Luchska) despite a reasonably well positioned ventricular catheter (Fig. 1), thus suggesting a distal end malfunction. Possible theories were (i) high intra-abdominal pressures associated with obesity which equilibrates the intracranial pressure and impairs CSF drainage due to back pressure (ii) intra-abdominal fat plugging the fenestrations at the distal end of the peritoneal catheter (iii) peritoneal adhesions from previous abdominal surgery (total abdominal hysterectomy).

Fig. 1.

Non-contrasted Computed Tomography Scan showing ventriculomegaly with marked 4th ventricular dilation with well placed ventricular catheter.

Whatever the reasons, an immediate revision of the distal (peritoneal catheter) became necessary and was conducted satisfactorily by construction of a fresh peritoneal catheter. Free flow of clear CSF was observed before re-internalisation of the new peritoneal catheter was done. The drainage slits at the distal end of the old peritoneal catheter were found to be clogged with fat which possibly contributed to the impaired drainage. Significant omental and peritoneal fat, as well as adhesions from previous laparotomy were also observed which may also have contributed to impaired drainage. She made a remarkable clinical and neurological improvement and a check scan on the 7th day post op revealed well decompressed ventricles (Fig. 2).

Fig. 2.

(a) 4th ventricles drained (b) lateral ventricles drained.

Check CT Brain 7 days post externalization of peritoneal catheter showing decompression of (a) 4th ventricle and (b) lateral ventricles.

However, from the ninth day post op, she was observed to become increasingly drowsy and lethargic with increasing headache, confusion and pupils became 3 mm and sluggishly reacting. Two sequential check brain scans conducted at two days interval revealed worsening hydrocephalus, the latter of the two is displayed in Fig. 3, and showed florid radiological features of pan-ventriculomegaly.

Fig. 3.

Axial cuts through the (a) 4th ventricle, (b) temporal horns and (c) lateral ventricles showing re-emergence of communicating hydrocephalus.

This situation necessitated a second revision of the peritoneal end of the shunt, but this time making a virgin access via an incision through the right lower abdomen with a new peritoneal catheter. The operative findings were a replica of the previous. It was therefore not surprising that post operatively, the improvement in her neurological status was only transient and two days later, externalization of the peritoneal catheter did not require much debate. An opening was made through the previous right lower abdominal scar and a gentle blunt dissection on the subcutaneous fat revealed the peritoneal catheter which was easily pulled out of the peritoneal cavity and adapted to an external drainage system (EDS). An immediate gush of clear CSF was observed and subsequent hourly CSF drainage monitoring revealed an average of 15–20 ml/h. A review of clinical neurology after 24 h revealed an awake, alert, stronger woman with excellent cognition and higher mental functions. GCS 15, Pupils 2 mm and briskly reactive, shunt valve refilled satisfactorily.

It was in no doubt at this point, after three revisions of the peritoneal catheter what and where the problem was. The dilemma therefore became alternative routes of drainage. The options were pleural cavity (ventriculo-pleural shunt), SVC/Right atrium (ventriculo-atrial (VA) shunt). Several MDT meetings were held with the Cardiothoracic and Vascular Surgeons in attendance. After a fortnight of deliberations, we settled for VA shunt; all the while, she remained neurologically and clinically stable on the EVD which drained an average of 10-15 ml/h.

One week later, the VA shunt procedure was successfully executed by a combined team of cardiovascular and neurosurgery. The neurosurgeon was a consultant with more than a decade of experience and this was his first time doing a VA shunt. Technique nuances involved appropriate patient positioning in a slight trendelenburg position.

Vascular Access- The right internal jugular vein was accessed percutaneously using a size 10Fr catheter using Seldinger technique. A peel away sheet was passed into the superior vena cava (SVC), the dilator was removed and distal aspect of the shunt was passed into the Right Atrium (RA) via the SVC under fluoroscopy, and sheet peeled away. Catheter position was confirmed under fluoroscopy. Neuro-anaesthesia provided confidence with continuous ECG monitoring throughout the procedure. Shunt was constructed via a transverse incision at the root of the neck, the passing shunt tubing was identified and a fresh distal catheter was passed through the dilator into the right atrium through the aperture of the peel away catheter which was gently peeled away. Shunt position was confirmed and adjusted to correct position under fluoroscopy guidance into the right atrium through the SVC (Fig. 4a).Redundant length of the distal catheter was amputated and adapted to the proximal end via the incision at the neck with a connector secured in place with silk 2.0 sutures. Post op she made an uneventful recovery on the usual post op medications -analgesics and antibiotics. Cognition and higher mental function as well as general strength in both upper and lower limbs remained satisfactory. A check chest Xray on the second post op day confirmed a well-positioned catheter on the SVC/RA axis (Fig. 4b). A check brain scan also revealed expectedly a satisfactory drainage of the ventricular systems (Fig. 5a, b, c).

Fig. 4.

a.-Intra-op fluoroscopic guidance of catheter tip (arrow) through SVC to RA. b- Post op check chest Xray localizing the catheter on the SVC/RA axis.

Fig. 5.

Check CT Brain Axial cuts through the (a) 4th ventricle, (b) temporal horns and (c) lateral ventricles two days post VA shunt, showing well decompressed ventricles.

After completion of Rocephin 1G 12hrly for a week post VA shunt she remained neurologically stable, though with residual imbalance but ambulated with little support. Post intervention concerns of thrombosis following a VA shunt were in mind and she was discharged home on daily rivaroxaban and aspirin. Patient reported full return to pre-morbid state and was satisfied with the care received and remained in good health with no neurologic signs at the 1 month and 3 months post op follow up visits.

4. Discussion

Although VP is reputed as the commonest method of long-term drainage of CSF in hydrocephalus, VA shunt has been in use since 1952 following the introduction of Spitz-Holter valve [6]. However, the enthusiasm and subsequent use of VA shunts was tempered by the recognition of a wide range of serious and even life-threatening complications especially related to cardiovascular issues. The subsequent introduction of VP shunts provided a basis for comparisons of t long-term results of the two types of shunts. This revealed that although both were equally effective, VP shunts were associated with a lower rate of revision (including prophylactic lengthening of the distal catheter) and of late and serious complications [7]. It is instructive to note that VP shunt is easier to place and revise and from the 1970s, it became the treatment of choice for most forms of hydrocephalus in children [8]^, [9]. In fact, the simplicity and efficacy of the VP shunt has sent the VA shunt to the drawer of last alternatives with very few recent reports on VA shunts. But despite the current bias towards VP shunt, recent reports suggest that, there is a critical mass of patient population where VA shunt is required [10]. As Celal Yavuz [1] and collaborators acknowledge, the VA shunt is a solution for a patient who has had already a set of complications. These complications are often secondary to the infectious aetiology of the hydrocephalus or the surgical aetiology associated with a “cold” peritoneum. For the index case, it is believed that a combination of surgical aetiology (extensive peritoneal adhesions secondary to complicated previous total abdominal hysterectomy), obesity and high intra-abdominal pressure constitute an unfavourable peritoneal cavity for free drainage and absorption of CSF. Of note is the role of high intra-abdominal pressure which may be complicated by back pressure in excess of the pressure on the VP shunt valve and also the prevailing intracranial pressure which will not encourage free flow of CSF. Recent advances and development of minimal invasive methods and radiographic guidance (fluoroscopy) has made VA shunt procedures and nuances quite surgeon friendly because percutaneous placement of a VA shunt with radiographic guidance improves the efficacy and safety of the technique [11].

.Although VA shunt provided a viable and attractive alternative in this situation of repeated failure of the peritoneal catheter for this patient, the possible complications are constantly in view and measures were assembled to forestall same. Obstructions, mal-position, and shunt infections are the most frequent problems in VA shunts [12]^, [13]. A sound application of percutaneous catheter placement under fluoroscopic guidance for the index case with expertise of the cardiovascular surgeon did not only improve the confidence of accurate placement on the right atrium but to immediately correct kinking of the catheter which was observed in this case which if not corrected immediately will potentially cause obstruction and early shunt malfunction. Continuous ECG monitoring by the neuro-anaesthetist further enhanced the confidence throughout the procedure with regards to prompt detection and management of any worrisome cardiac arrhythmias during catheter placement on the right atrium. And fortunately, no such was recorded in this case. Peri-operative administration of 1G Rocephin (ceftriaxone) and post op continuation of 1G Rocephin 12 hourly for one week was aimed at forestalling any catheter related infections including the life-threatening ones such as infective endocarditis as reported by Chaw, et al. in one VA shunt case [14]. Another issue of concern is thrombotic events which can potentially be associated with such an implant in the heart. Early complications of catheter thrombosis were seen in one patient on the 15th day following operation [1]. Consequently, index patient was adequately covered with daily rivaroxaban and 75 mg ASA and will remain on monthly blood and clotting profile checks. In the meantime, she remains neurologically and clinically sound.

5. Conclusion

VA shunts are indispensable options for cerebrospinal fluid drainage in hydrocephalus. However, patient selection, surgical expertise, enabled equipment base, sound anaesthesia and monitoring remains the key to successful placement. Perhaps more important to long term success is proactive surveillance and early management of potential complications especially infective and thrombotic events which have been reported as potentially fatal if neglected.

Source of funding

None.

Ethical approval

Ethical standards were reviewed and approved by the Wellington Clinics Abuja.

Guarantors

Ugochukwu C. Ugwuanyi.

Ndubuisi Anumenechi.

Consent

Written informed consent was obtained from the patient for publication of this case report and accompanying images. A copy of the written consent is available for review by the Editor-in-Chief of this journal on request.

CRediT authorship contribution statement

Ugwuanyi Charles, Anumenechi Ndubuisi and Okpata Cyril operated on this patient.

Morayo Salawu provided intra-operative anaesthesia. Onobun Daniel and Adeoti Ebenezer were responsible for post-operative care of the patient.

Paper was written by Onobun Daniel, Adeoti Ebenezer and Ugwuanyi Charles.

Research registration

N/A.

Provenance and peer review

Not commissioned, externally peer-reviewed.

Declaration of competing interest

The authors report no conflict of interest.