Shunt malfunction

Shunt malfunction

Cerebrospinal fluid diversion by way of ventriculoperitoneal shunt (or other terminus) is a commonly performed neurosurgical procedure but one that is fraught with high rates of failure. Up to one-third of adult patients undergoing CSF shunting will experience a shunt failure 1).

Shunt dysfunction or failure was defined as shunt revision, subsequent endoscopic third ventriculostomy, or shunt infection 2).

Mechanical shunt obstruction is the most common reason for failure, and in proximal catheter failure, this typically means obstruction by the choroid plexus 3).

Shunt surgery consumes a large amount of pediatric neurosurgical health care resources. Although many studies have sought to identify risk factors for shunt failure, there is no consensus within the literature on variables that are predictive or protective.

Patients with cerebrospinal fluid shunts frequently present to the emergency department (ED) with suspected shunt malfunction.

Once there is a suspicion of a shunt dysfunction, a CT scan or MRI scan is used to compare the ventricular size and show the most definitive signs of a malfunction. This is only useful if a previous scan can be used for comparison. In cases where the symptoms of a shunt malfunction are present but the scanning shows no evidence, the next step involves a shunt tap test.

Mechanical failure-which is the primary cause of CSF shunt malfunction-is not readily diagnosed, and the specific reasons for mechanical failure are not easily discerned. Prior attempts to measure cerebrospinal fluid flow noninvasively have lacked the ability to either quantitatively or qualitatively obtain data.

To address these needs, a preliminary study evaluates an ultrasonic transit time flow sensor in pediatric and adult patients with external ventricular drainages (EVDs). One goal was to confirm the stated accuracy of the sensor in a clinical setting. A second goal was to observe the sensor’s capability to record real-time continuous CSF flow. The final goal was to observe recordings during instances of flow blockage or lack of flow in order to determine the sensor’s ability to identify these changes.

A total of 5 pediatric and 11 adult patients who had received EVDs for the treatment of hydrocephalus were studied in a hospital setting. The primary EVD was connected to a secondary study EVD that contained a fluid-filled pressure transducer and an in-line transit time flow sensor. Comparisons were made between the weight of the drainage bag and the flow measured via the sensor in order to confirm its accuracy. Data from the pressure transducer and the flow sensor were recorded continuously at 100 Hz for a period of 24 hours by a data acquisition system, while the hourly CSF flow into the drip chamber was recorded manually. Changes in the patient’s neurological status and their time points were noted.

The flow sensor demonstrated a proven accuracy of ± 15% or ± 2 ml/hr. The flow sensor allowed real-time continuous flow waveform data recordings. Dynamic analysis of CSF flow waveforms allowed the calculation of the pressure-volume index. Lastly, the sensor was able to diagnose a blocked catheter and distinguish between the blockage and lack of flow.

The Transonic flow sensor accurately measures CSF output within ± 15% or ± 2 ml/hr, diagnoses the blockage or lack of flow, and records real-time continuous flow data in patients with EVDs. Calculations of a wide variety of diagnostic parameters can be made from the waveform recordings, including resistance and compliance of the ventricular catheters and the compliance of the brain. The sensor’s clinical applications may be of particular importance to the noninvasive diagnosis of shunt malfunctions with the development of an implantable device 4).

Classification

Shunt overdrainage

Shunt disconnection

Shunt obstruction

Shunt migration

Ventricular catheter misplacement

see Ventriculoperitoneal shunt malfunction

Distal shunt malfunction due to a mechanical failure is a common reason for shunt revision 5).

As many as one third of patients presenting with shunt malfunction will not have the diagnosis of shunt malfunction supported by a prospective radiologic interpretation of brain imaging. Although the neurosurgical community can assess the clinical situation to determine the need for surgery, other clinicians can be easily reassured by a radiographic report that does not mention or diagnose shunt malfunction. Today, more than ever, nonneurosurgeons are being called on to evaluate complex clinical situations and may rely on radiographic reports 6).

Diagnosis

Various invasive diagnostic test procedures for the verification of shunt function have been described:

Invasive CSF pressure and flow measurements

CSF tap test and drip interval test

Infusion tests

Radioactive shuntogram.

By comparison, publications addressing the noninvasive pumping test are rare.

Noninvasive pumping test of all formerly published results are values derived from tests with a variety of reservoirs and valves (at least 2 types).

In a few reports, the shunt/reservoir type used is not even specified, although the technical parameters of such reservoirs and valves are obviously essential.

To judge occlusions distally from the reservoir other authors have had to close the pVC transcutaneously by manual compression.

This is never possible with a sufficient certainty and, if ever undertaken, it usually does provide a source of error.


Rapid cranial MRI was not inferior to CT for diagnosing ventricular shunt malfunction and offers the advantage of sparing a child ionizing radiation exposure 7).

Treatment

ETV can be considered a primary treatment modality in children with shunt malfunction and has a good success rate in cases presenting with closure of previously performed ETV stoma 8).

Outcome

Case series

Case reports

1)

Reddy GK, Bollam P, Shi R, Guthikonda B, Nanda A: Management of adult hydrocephalus with ventriculoperitoneal shunts: long-term single-institution experience. Neurosurgery 69:774–781, 2011
2)

Riva-Cambrin J, Kestle JR, Holubkov R, Butler J, Kulkarni AV, Drake J, Whitehead WE, Wellons JC 3rd, Shannon CN, Tamber MS, Limbrick DD Jr, Rozzelle C, Browd SR, Simon TD; Hydrocephalus Clinical Research Network. Risk factors for shunt malfunction in pediatric hydrocephalus: a multicenter prospective cohort study. J Neurosurg Pediatr. 2016 Apr;17(4):382-90. doi: 10.3171/2015.6.PEDS14670. Epub 2015 Dec 4. PubMed PMID: 26636251.
3)

Korinek AM, Fulla-Oller L, Boch AL, Golmard JL, Hadiji B, Puybasset L: Morbidity of ventricular cerebrospinal fluid shunt surgery in adults: an 8-year study. Neurosurgery 68:985–995, 2011
4)

Pennell T, Yi JL, Kaufman BA, Krishnamurthy S. Noninvasive measurement of cerebrospinal fluid flow using an ultrasonic transit time flow sensor: a preliminary study. J Neurosurg Pediatr. 2016 Mar;17(3):270-7. doi: 10.3171/2015.7.PEDS1577. Epub 2015 Nov 13. PubMed PMID: 26565943.
5)

Sribnick EA, Sklar FH, Wrubel DM. A Novel Technique for Distal Shunt Revision: Retrospective Analysis of Guidewire-Assisted Distal Catheter Replacement. Neurosurgery. 2015 May 1. [Epub ahead of print] PubMed PMID: 25938689.
6)

Iskandar BJ, McLaughlin C, Mapstone TB, Grabb PA, Oakes WJ. Pitfalls in the diagnosis of ventricular shunt dysfunction: radiology reports and ventricular size. Pediatrics. 1998 Jun;101(6):1031-6. PubMed PMID: 9606231.
7)

Boyle TP, Paldino MJ, Kimia AA, Fitz BM, Madsen JR, Monuteaux MC, Nigrovic LE. Comparison of rapid cranial MRI to CT for ventricular shunt malfunction. Pediatrics. 2014 Jul;134(1):e47-54. doi: 10.1542/peds.2013-3739. Epub 2014 Jun 2. PubMed PMID: 24918222.
8)

Shaikh S, Deopujari CE, Karmarkar V, Muley K, Mohanty C. Role of Secondary Endoscopic Third Ventriculostomy in Children: Review of an Institutional Experience. Pediatr Neurosurg. 2019 Jun 3:1-8. doi: 10.1159/000500641. [Epub ahead of print] PubMed PMID: 31158842.

Plexiform neurofibroma treatment

Plexiform neurofibroma treatment

Since plexiform neurofibromas are a major cause of the burden of disease and may also progress to malignancy, many efforts have been undertaken to find a cure for these tumors. However, neither surgery nor medication has so far produced a breakthrough therapeutic success.

Plexiform neurofibromas with sizable intraspinal extensions and resultant spinal cord compromise pose challenging management problems, because these lesions may involve multiple nerves and engulf adjacent vascular and visceral structures 1).

Decisions about surgical treatment and frequency of follow-up must be made judiciously and individualized for each patient 2).

Plexiform neurofibromas arising in the orbito-temporal area pose a greater challenge due to its critical function and cosmetic importance of the face. Such plexiform neurofibromas, separately designated as orbito-temporal plexiform neurofibromas, show complex symptoms such as severe ptosis, ectropion, lacrimal gland dysfunction, and even vision loss 3).


A clinical phase I study reported significant shrinkage of plexiform neurofibromas following treatment with the MEK inhibitor selumetinib.

Vaassen et al., reported an 11-year-old NF1 patient with a large plexiform neurofibroma of the neck that had led to a sharp-angled kinking of the cervical spine and subsequent myelopathy. Although surgical stabilization of the cervical vertebral column was urgently recommended, the vertebral column was inaccessible due to extensive tumor growth. In this situation, treatment with the MEK inhibitor trametinib was initiated which resulted in a 22% reduction in tumor volume after 6 months of therapy and finally enabled surgery. These data show that MEK inhibitors may not lead to complete disappearance of NF1-associated plexiform neurofibromas but can be an essential step in a multimodal therapeutic approach for these tumors. The course of our patient suggests that MEK inhibitors are likely to play a significant role in providing a cure for one of the most devastating manifestations of NF1 4).

References

1)

Pollack IF, Colak A, Fitz C, Wiener E, Moreland M, Mulvihill JJ. Surgical management of spinal cord compression from plexiform neurofibromas in patients with neurofibromatosis 1. Neurosurgery. 1998 Aug;43(2):248-55; discussion 255-6. PubMed PMID: 9696077.
2)

Gutmann DH, Aylsworth A, Carey JC, Korf B, Marks J, Pyeritz RE, Rubenstein A, Viskochil D. The diagnostic evaluation and multidisciplinary management of neurofibromatosis 1 and neurofibromatosis 2. JAMA. 1997 Jul 2;278(1):51-7. Review. PubMed PMID: 9207339.
3)

Choi J, Choi HJ, Kang KJ, Kwon H, Shin J. Simultaneous Forehead Lift and Blepharoplasty Techniques in Management of Orbito-Temporal Plexiform Neurofibroma. J Craniofac Surg. 2019 Mar 14. doi: 10.1097/SCS.0000000000005448. [Epub ahead of print] PubMed PMID: 30889063.
4)

Vaassen P, Dürr N, Röhrig A, Willing R, Rosenbaum T. Trametinib Induces Neurofibroma Shrinkage and Enables Surgery. Neuropediatrics. 2019 May 29. doi: 10.1055/s-0039-1691830. [Epub ahead of print] PubMed PMID: 31141829.

Cerebellar hemorrhage surgery

Cerebellar hemorrhage surgery

In 1906, Ballance first reported a surgical approach to treatment of cerebellar hemorrhage1) 2).

Since then, surgical treatment has become the general option for treatment 3).

Recommendations from Kobayashi et al in 1994 4)

1. patients with a Glasgow Coma Scale (GCS) score ≥14 and hematoma <4 cm diameter: treat conservatively

2. patients with GCS≤13 or with a hematoma ≥4 cm: surgical evacuation.

3. patients with absent brain stem reflexes and flaccid quadriplegia: intensive therapy is not indi- cated. Note: some authors contend that the loss of brain stem reflexes from direct compression may not be irreversible, 5) and that cerebellar hemorrhage represents a surgical emergency (and that the above criteria would thus deny potentially helpful surgery to some, see discussion of cerebellar infarction and decompression.

4. patients with hydrocephalus: ventricular catheter (if no coagulopathy). Caution: do not overdrain to avoid upward cerebellar herniation. Most cases with hydrocephalus also require evacuation of the clot

Criteria

Surgical treatment of cerebellar ICH can be life-saving but often leads to a poor functional outcome. New studies are needed on long-term functional outcome after a cerebellar ICH 6).

Since the 1970s, there has been a wide mutual consensus in the neurological and neurosurgical community that cerebellar ICHs should be operated on. However, the scientific proof is mainly based on small retrospective series with conflicting results 7).

To relieve brainstem compression and hydrocephalus, surgeons tend to favor occipital craniectomy or occipital craniotomy with hematoma evacuation in patients with a declining level of consciousness 8). Some regard this counterintuitive as long-term outcomes after surgical treatment of cerebellar ICH are generally pessimistic 9).


Since the report by Little et al., 10) the hematoma diameter has been considered a significant factor in the decision-making process for optimal treatment.

The criteria for surgery remain controversial, and many researchers have determined that a hematoma larger than 3 cm, obstruction of the quadrigeminal cistern, and compression of the fourth ventricle are surgical criteria 11) 12) 13).

Cohen et al. 14) used a maximal hematoma diameter greater than 3 cm as the surgical criterion, however, some patients with a hematoma larger than 3 cm who underwent conservative treatment had a good prognosis as well. In addition, a hematoma volume greater than 15 mL, being equivalent with a hematoma with a maximal diameter greater than 3 cm, has also been used as a criterion in some cases 15).


The criteria of Kobayashi et al., are as follows:

1) patients with Glasgow Coma Scale scores of 14 or 15 and with a hematoma of less than 40 mm in maximum diameter are treated conservatively

2) for the patients with Glasgow Coma Scale scores of 13 or less at admission or with a hematoma measuring 40 mm or more, hematoma evacuation with decompressive suboccipital craniectomy should be a treatment of choice

3) for the patient whose brain stem reflexes are entirely lost with flaccid tetraplegia or whose general condition is poor, intensive therapy is not indicated. The validity of these criteria was tested and confirmed in 49 cases 16).

Technique

Position

Lateral oblique position with the involved side up.

If rapidity is crucial a suboccipital midline skin incision is preferred because it can be taken down quickly with little fear of encountering a vertebral artery.

Suboccipital craniectomy is preferred over suboccipital craniotomy to accomodate postoperative swelling.

A prophylactically ventriculostomy at Frazier’s point is recommended to allow rapid treatment of postoperative hydrocephalus or intracranial pressure monitoring.

In cases where there has been rupture into the ventricular system, the surgical microscope should be used to follow the clot to the fourth ventriclewhich is then cleared of clot.

External ventricular drainage (EVD) combined with intraventricular thrombolysis (IVF) is rarely used in severe spontaneous cerebellar hemorrhage(SCH) with intraventricular hemorrhage (IVH).

It is a treatment option for elderly patients with severe SCH + IVH 17).

Video

References

1) , 15)

Cho SM, Hu C, Pyen JS, Whang K, Kim HJ, Han YP, et al. Predictors of outcome of spontaneous cerebellar hemorrhage. J Korean Neurosurg Soc. 1997 Oct;26(10):1395–1400.
2) , 3)

Dahdaleh NS, Dlouhy BJ, Viljoen SV, Capuano AW, Kung DK, Torner JC, Hasan DM, Howard MA 3rd. Clinical and radiographic predictors of neurological outcome following posterior fossa decompression for spontaneous cerebellar hemorrhage. J Clin Neurosci. 2012 Sep;19(9):1236-41. doi: 10.1016/j.jocn.2011.11.025. Epub 2012 Jun 20. PubMed PMID: 22721890.
4)

Kobayashi S, Sato A, Kageyama Y, et al. Treatment of Hypertensive Cerebellar Hemorrhage – Surgical or Conservative Management. Neurosurgery. 1994; 34:246–251
5)

Heros RC. Surgical Treatment of Cerebellar Infarc- tion. Stroke. 1992; 23:937–938
6)

Satopää J, Meretoja A, Koivunen RJ, Mustanoja S, Putaala J, Kaste M, Strbian D, Tatlisumak T, Niemelä MR. Treatment of intracerebellar haemorrhage: Poor outcome and high long-term mortality. Surg Neurol Int. 2017 Nov 9;8:272. doi: 10.4103/sni.sni_168_17. eCollection 2017. PubMed PMID: 29204307; PubMed Central PMCID: PMC5691556.
7)

Witsch J, Neugebauer H, Zweckberger K, Jüttler E. Primary cerebellar haemorrhage: complications, treatment and outcome. Clin Neurol Neurosurg. 2013 Jul;115(7):863-9. doi: 10.1016/j.clineuro.2013.04.009. Epub 2013 May 6. Review. PubMed PMID: 23659765.
8)

Wijdicks EF, St Louis EK, Atkinson JD, Li H. Clinician’s biases toward surgery in cerebellar hematomas: an analysis of decision-making in 94 patients. Cerebrovasc Dis. 2000 Mar-Apr;10(2):93-6. PubMed PMID: 10686446.
9)

Luney MS, English SW, Longworth A, Simpson J, Gudibande S, Matta B, Burnstein RM, Veenith T. Acute Posterior Cranial Fossa Hemorrhage-Is Surgical Decompression Better than Expectant Medical Management? Neurocrit Care. 2016 Dec;25(3):365-370. PubMed PMID: 27071924; PubMed Central PMCID: PMC5138260.
10)

Little JR, Tubman DE, Ethier R. Cerebellar hemorrhage in adults. Diagnosis by computerized tomography. J Neurosurg. 1978 Apr;48(4):575-9. PubMed PMID: 632882.
11) , 14)

Cohen ZR, Ram Z, Knoller N, Peles E, Hadani M. Management and outcome of non-traumatic cerebellar haemorrhage. Cerebrovasc Dis. 2002;14(3-4):207-13. PubMed PMID: 12403953.
12)

Kirollos RW, Tyagi AK, Ross SA, van Hille PT, Marks PV. Management of spontaneous cerebellar hematomas: a prospective treatment protocol. Neurosurgery. 2001 Dec;49(6):1378-86; discussion 1386-7. PubMed PMID: 11846937.
13)

Salvati M, Cervoni L, Raco A, Delfini R. Spontaneous cerebellar hemorrhage: clinical remarks on 50 cases. Surg Neurol. 2001 Mar;55(3):156-61; discussion 161. PubMed PMID: 11311913.
16)

Kobayashi S, Sato A, Kageyama Y, Nakamura H, Watanabe Y, Yamaura A. Treatment of hypertensive cerebellar hemorrhage–surgical or conservative management? Neurosurgery. 1994 Feb;34(2):246-50; discussion 250-1. PubMed PMID: 8177384.
17)

Zhang J, Wang L, Xiong Z, Han Q, Du Q, Sun S, Wang Y, You C, Chen J. A treatment option for severe cerebellar hemorrhage with ventricular extension in elderly patients: intraventricular fibrinolysis. J Neurol. 2014 Feb;261(2):324-9. doi: 10.1007/s00415-013-7198-2. Epub 2013 Dec 3. PubMed PMID: 24297364.
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