Ommaya reservoir is a ventricular access device for the purpose of repetitive access to the intrathecal space. This device is named after its inventor, a Pakistani neurosurgeon Ayub Khan Ommaya in 1963. Though initially conceived for delivery of antifungal medications into the cerebrospinal fluid (CSF), this device is commonly used today for chemotherapeutic central nervous system (CNS) delivery and CSF sampling. The Ommaya reservoir has replaced repeated intrathecal injections (via lumbar or suboccipital puncture) in the administration of antineoplastic drug delivery. This device permits repeated administration of chemotherapeutic drugs without doing a lumbar puncture, allows CSF sampling for dose titration, and provides consistent intrathecal drug concentrations.
For many decades, the Ommaya reservoir was inserted by a freehand technique. If ventriculomegaly is not present, accurate placement of the ventricular end may often be difficult. Multiple attempts through the brain cortex can result in complications such as hemorrhage, intracranial infection, and seizures. Computed tomography assisted stereotactic placement of the Ommaya reservoir for small or normal-sized ventricles formed the basis for future neuronavigation techniques. Since then, the insertion of the intraventricular catheter has undergone a major transformation, aided by high-resolution imaging techniques and advances in neuronavigation such as optical tracking frameless stereotactic approach, electromagnetic tracking, frame-based tracking, fluoroscopy-assisted, ultrasound-guided and endoscope-guided implantations.
Ommaya reservoir consists of an indwelling ventricular catheter with a dome-shaped collapsible silicone reservoir port positioned under the scalp. The distal end of the catheter is surgically positioned into the ipsilateral anterior horn with the proximal end connected to the reservoir.
The prerequisite knowledge and skill required for this procedure is an extension of a frontal ventriculostomy procedure. A frontal ventriculostomy is one of the most common neurosurgical procedures. The target of an ideal ventriculostomy is at the center of the anterior horn. Kocher described the entry point for the ventriculostomy as "2.5 cm to 3 cm from the median line and 3 cm anterior to the precentral fissure." The recommendations for the entry point in the literature vary from 1.5 cm to 4 cm from the midline, and from 10 cm to 12.5 cm posterior to the nasion (1 cm to 2 cm anterior to the coronal suture). Though there have been numerous definitions of Kocher's point in literature, the common principles governing the site of entry involve avoiding injury to the sagittal sinus, bridging veins, basal ganglia, frontal eye fields, and the motor cortex. Nowadays, Kocher's point is better described as an entry point that is 11 cm superior and posterior from the nasion, 3 cm lateral to midline along the mid pupillary line, and 1 cm to 2 cm anterior to the coronal suture. The recommended trajectory in the sagittal plane is downward and backward, targetting the external auditory meatus or 1 cm to 1.5 cm anterior to the tragus. In the coronal plane, the targets vary from either perpendicular puncture to towards contralateral medial canthus, nasion, or ipsilateral medial canthus. The most robust entry point and trajectory with the highest hit rate follow the 3-2-1 rule, i.e., entering at a point 3 cm lateral to the midline and 2 cm anterior to the bregma by targetting the contralateral medial canthus and 1 cm anterior to the tragus.
Ommaya reservoir can be used for several procedures where medications are injected into the intrathecal space, CSF is aspirated, or where tumoral cyst fluid is removed. The major indications are enumerated below.
Optional Intraoperative Technology
A complete team for insertion of Ommaya reservoir would include a trained neurosurgeon, nurse, operating practitioner, and an anesthetist.
The procedure is performed under general anesthesia unless contraindicated. The patient is placed in a supine position with the head fixed on a Mayfield clamp holder. Preoperative computed tomography (CT) scan or magnetic resonance imaging (MRI) is assessed for any lateralizing lesions or ventricular asymmetry. The preferred site of insertion is the right frontal region unless indicated for a tumor cyst or if there is an anterior horn asymmetry which favors a left-sided approach. Pre-soaking the reservoir system in an antibiotic saline solution is recommended.
Image-guided Technique: Preoperative neuronavigation CT scan or MRI with adhesive fiducial markers is performed before surgery. Preoperative imaging is loaded into the image guidance system, followed by a delineation of entry and target points on the surgical planning software. The entry point is through the crown of a gyrus avoiding cortical vessels. The target point is directed to the ipsilateral foramen of Monro. The passive reference frame of the image guidance system is attached to the articulating arm of the Mayfield clamp holder. Fiducial registration is performed, and image-guidance accuracy is checked.
The surgical site is prepared and then cleaned and draped under aseptic precautions. An inverted U shaped scalp incision slightly larger than the diameter of the Ommaya reservoir (3.4 cm) is made over the entry point. The center of the incision overlies the Kocher point, located 3 cms lateral to the midline at the mid pupillary line and 1 cm anterior to the coronal suture. A pericranial flap is raised to fit the size of the Ommaya reservoir. A burr hole is made, followed by a cruciate durotomy. Minimal bipolar coagulation of the cortical surface is encouraged. A pial/cortical incision is made, avoiding any surface vessel. Image-guided navigation can significantly improve the accuracy of the target point. A Dandy needle with an optical tracker is registered with the image guidance system. The trajectory of insertion is as planned via the image guidance system. If done via freehand placement, the trajectory of insertion is placed perpendicular to the calvarium or towards a coronal plane 2 cm anterior to the external auditory meatus and directed towards contralateral medial canthus. Entry into the ventricle can be identified by a "pop sensation" and free flow of CSF. The catheter is inserted along the brain needle trajectory. The length of the catheter is cut as estimated according to preoperative imaging (roughly 5 cm to 5.5 cm when measured at the inner table of the calvarium) and attached to the base of the reservoir with a silk tie. This length allows the tip of the catheter to be positioned near the floor of the anterior horn of the lateral ventricle. The correct placement of the catheter can be verified with an image guidance system. The pericranial flap is repositioned over the reservoir and sutured back. The scalp is closed in two layers. Skin marking with India ink could be used to identify the correct position of the dome. In the postoperative period, a head CT scan is performed to evaluate the catheter placement and any evidence of hemorrhage.
The scalp is prepared with antiseptic scrub. The dome of the reservoir is palpated and ascertained. Using a 25 gauge or thinner needle, the reservoir is pierced in an oblique fashion and then aspirated. The internal capacity of the reservoir for adults varies from 1.5 ml to 2.4 ml. After the aspiration, the therapeutic medication is injected, and the needle is withdrawn. For tumors, the cyst contents are aspirated slowly until the desired amount is obtained. The patient is monitored for 2 hours in a supine position to rule out any neurological deterioration.
Ommaya reservoirs are used for the administration of drugs into the intrathecal space, primarily for CNS hematological malignancies and also for drainage of intracranial cystic tumors. These devices are implanted by neurosurgeons under general anesthesia. Immediate postoperative care and repeated tumor cyst drainage would involve coordination between the neurosurgeons and the neurosurgical nursing team. These reservoirs are accessed by hematologists and oncologists for the administration of chemotherapeutic drugs and CSF sampling for dose titration, as early as the day of operation. Radiologists play a part in their management as these patients often require imaging to assess for intracranial disease/tumor staging or, rarely, for malfunctioning of the device. General practitioners and community nursing staff should be aware and able to identify early signs of infection. Once the skin heals, these devices do not require any special care. They can remain in place for months to years. [Level 5]
Nurses and allied health staff involved in the care of patients with Ommaya reservoirs need to be aware of the following:
The nurses involved in the surveillance of patients with an Ommaya reservoir should monitor for:
|||Ommaya AK, Subcutaneous reservoir and pump for sterile access to ventricular cerebrospinal fluid. Lancet (London, England). 1963 Nov 9; [PubMed PMID: 14059058]|
|||Witorsch P,Williams TW Jr,Ommaya AK,Utz JP, Intraventricular administration of amphotericin B. Use of subcutaneous reservoir in four patients with mycotic meningitis. JAMA. 1965 Nov 15; [PubMed PMID: 5898006]|
|||Ratcheson RA,Ommaya AK, Experience with the subcutaneous cerebrospinal-fluid reservoir. Preliminary report of 60 cases. The New England journal of medicine. 1968 Nov 7; [PubMed PMID: 5303038]|
|||Dossani RH,Kalakoti P,Thakur JD,Nanda A, Ayub Khan Ommaya (1930-2008): Legacy and Contributions to Neurosurgery. Neurosurgery. 2017 Feb 1; [PubMed PMID: 28173516]|
|||Hagen NA,O'Neill BP,Kelly PJ, Computer assisted stereotactic placement of Ommaya reservoirs for delivery of chemotherapeutic agents in cancer patients. Journal of neuro-oncology. 1987; [PubMed PMID: 3316522]|
|||Lane J,Zacharia BE, Endoscopic-Assisted Ommaya Reservoir Placement: Technical Note. Cureus. 2017 Jul 19 [PubMed PMID: 28944129]|
|||Hildebrandt G,Surbeck W,Stienen MN, Emil Theodor Kocher: the first Swiss neurosurgeon. Acta neurochirurgica. 2012 Jun; [PubMed PMID: 22492296]|
|||Morone PJ,Dewan MC,Zuckerman SL,Tubbs RS,Singer RJ, Craniometrics and Ventricular Access: A Review of Kocher's, Kaufman's, Paine's, Menovksy's, Tubbs', Keen's, Frazier's, Dandy's, and Sanchez's Points. Operative neurosurgery (Hagerstown, Md.). 2020 May 1; [PubMed PMID: 31420653]|
|||Srikandarajah N,Patel A,Lee MK,Brodbelt A, Indications for intracranial reservoirs: a six-year study. British journal of neurosurgery. 2014 Aug [PubMed PMID: 24199941]|
|||Takahashi M,Yamada R,Tabei Y,Nakamura O,Shinoura N, Navigation-guided Ommaya reservoir placement: implications for the treatment of leptomeningeal metastases. Minimally invasive neurosurgery : MIN. 2007 Dec [PubMed PMID: 18210356]|
|||Lau JC,Kosteniuk SE,Macdonald DR,Megyesi JF, Image-guided Ommaya reservoir insertion for intraventricular chemotherapy: a retrospective series. Acta neurochirurgica. 2018 Mar [PubMed PMID: 29305723]|
|||Huyette DR,Turnbow BJ,Kaufman C,Vaslow DF,Whiting BB,Oh MY, Accuracy of the freehand pass technique for ventriculostomy catheter placement: retrospective assessment using computed tomography scans. Journal of neurosurgery. 2008 Jan; [PubMed PMID: 18173315]|
|||Kormanik K,Praca J,Garton HJ,Sarkar S, Repeated tapping of ventricular reservoir in preterm infants with post-hemorrhagic ventricular dilatation does not increase the risk of reservoir infection. Journal of perinatology : official journal of the California Perinatal Association. 2010 Mar [PubMed PMID: 19812582]|
|||Rogers LR,Barnett G, Percutaneous aspiration of brain tumor cysts via the Ommaya reservoir system. Neurology. 1991 Feb [PubMed PMID: 1992376]|
|||Joki T,Oi S,Babapour B,Kaito N,Ohashi K,Ebara M,Kato M,Abe T, Neuroendoscopic placement of Ommaya reservoir into a cystic craniopharyngioma. Child's nervous system : ChNS : official journal of the International Society for Pediatric Neurosurgery. 2002 Nov [PubMed PMID: 12420123]|
|||Gutin PH,Klemme WM,Lagger RL,MacKay AR,Pitts LH,Hosobuchi Y, Management of the unresectable cystic craniopharyngioma by aspiration through an Ommaya reservoir drainage system. Journal of neurosurgery. 1980 Jan [PubMed PMID: 7350278]|
|||Mead PA,Safdieh JE,Nizza P,Tuma S,Sepkowitz KA, Ommaya reservoir infections: a 16-year retrospective analysis. The Journal of infection. 2014 Mar; [PubMed PMID: 24321561]|
|||Bin Nafisah S,Ahmad M, Ommaya reservoir infection rate: a 6-year retrospective cohort study of Ommaya reservoir in pediatrics. Child's nervous system : ChNS : official journal of the International Society for Pediatric Neurosurgery. 2015 Jan; [PubMed PMID: 25301010]|
|||Szvalb AD,Raad II,Weinberg JS,Suki D,Mayer R,Viola GM, Ommaya reservoir-related infections: clinical manifestations and treatment outcomes. The Journal of infection. 2014 Mar; [PubMed PMID: 24360921]|
|||Bauer DF,Razdan SN,Bartolucci AA,Markert JM, Meta-analysis of hemorrhagic complications from ventriculostomy placement by neurosurgeons. Neurosurgery. 2011 Aug; [PubMed PMID: 21471831]|
|||Kosier MB,Minkler P, Nursing management of patients with an implanted Ommaya reservoir. Clinical journal of oncology nursing. 1999 Apr [PubMed PMID: 10633613]|
|||Esparza DM,Weyland JB, Nursing care for the patient with an Ommaya reservoir. Oncology nursing forum. 1982 Fall [PubMed PMID: 6923413]|