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|Year : 2020 | Volume
| Issue : 3 | Page : 652-653
Suction Pressure Control Valve for Microneurosurgery
Abhijeet S Barath1, Om P Thakur2, Mayank Garg1, Suryanarayanan Bhaskar1, Deepak K Jha1
1 Department of Neurosurgery, All India Institute of Medical Sciences, Jodhpur, India
2 School of Basic and Applied Sciences, Raffles University, Neemrana, Alwar Rajasthan, India
|Date of Web Publication||6-Jul-2020|
Dr. Deepak K Jha
Department of Neurosurgery, All India Institute of Medical Sciences, Jodhpur - 342 005, Rajasthan
Source of Support: None, Conflict of Interest: None
A suction pressure control valve (SPCV) for microneurosurgery is designed to place control of safe suction pressure in the hands of an operating neurosurgeon. Tumor tissue needs more negative suction pressure as compared to normal brain tissue, cranial nerves, and vessels in the neurosurgical operating field. The authors present the details of a prototype of a simple and inexpensive device for dynamic adjustment of negative suction pressure by the surgeon or the assistant while working on different tissue types during microneurosurgery.
Keywords: Frugal innovation, neurosurgical suction, threshold suction pressure
Key Messages: Suction is a key operating instrument for any neurosurgeon. The neurosurgeon uses thumb control air leak hole system continuously to change negative suction pressure depending upon the tissue being dissected. Having an additional simple, inexpensive negative suction pressure controlling tool in addition to thumb control air leak hole system will make the surgeon control it more easily in a better way, which will make the surgery safer.
|How to cite this article:|
Barath AS, Thakur OP, Garg M, Bhaskar S, Jha DK. Suction Pressure Control Valve for Microneurosurgery. Neurol India 2020;68:652-3
Central or portable suction systems used in operating rooms (OR) have valves, controlled by OR personnel, for adjustment of suction pressure. Safe threshold suction pressure for cortical tissue has been established in animal models and varies from one tissue type to another. Methods and devices such as use of cotton patties, suction tip modifications,, thumb-controlled air leak holes,, and in-line suction control valve  have evolved. Their limitations include obscured surgical field, inability to prevent water hammer effect, high cost, and limited range of pressure adjustments. The senior author (DKJ) has designed a simple, inexpensive, and effective suction pressure control valve (SPCV), which addresses these limitations and can be directly controlled by the surgeon or the assistant for safe microneurosurgical procedures.
Design of SPCV
SPCV is a coaxial tube system of two tubes made up of surgical-grade stainless steel [Figure 1]. The inner long tube (Ti) has a length of 120 mm with inner (ID) and outer diameters (OD) of 6.6 mm and 8 mm, respectively. It has an elongated slit (Si) of 13 mm × 2.5 mm in the middle along its length. The outer shorter tube (To) has a length of 45 mm with ID 8 mm and OD 10 mm. It has a 1.8-mm wide slit (So) along its entire length for better grip over the Ti by clipping action. To fits snuggly over Ti and can slide over it easily [Figure 2]. While in use, So is placed opposite to Si. The tube is placed within the sterile surgical field and is connected in line with the suction tube at about 1 meter from the suction tip [Figure 3].
|Figure 1: Components of suction pressure control valve (SPCV) showing inner (Ti) and outer (To) tubes with slits over inner (Si) and outer (So) tubes|
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|Figure 2: SPCV with Sifully open (a), partially open (b), and fully closed (c) by To|
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|Figure 3: SPCV connected in the suction tubing in the surgical field with Si of Tifully closed by To|
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Negative suction pressure can be set to minimum when Si is fully opened [Figure 2]a and maximum when Si is fully closed [Figure 2]c by sliding To over Ti. Exposed length of Si is controlled by the surgeon or the assistant to set the safe negative suction pressure as per tissue type being dealt with.
| » Discussion|| |
Literatures since 1960s show numerous efforts for safe suction in neurosurgery.,,,,,, Most of them are associated with complex arrangements of additional tubes, holes, or slits in the suction tips which seem effective but not without risk of sudden bursts of negative pressure.,,
Currently, suction tips with thumb control are the most commonly used method for control of negative pressure by the neurosurgeons in conjunction with the main pressure control valve, which is controlled by the OR personnel. However, it fails to change the negative pressure in a smooth fashion. Sudden increase in the negative pressure may be disastrous in the settings of microneurosurgery. Neurosurgeons control suction pressure most commonly by using thumb to close or release the hole (circular or tear-drop) in the suction tips. However this particular method of precisely controlling the suction pressure is perhaps one of the most important surgical skills, which comes with experience. Cottonoids are routinely used to prevent inadvertent trauma to the neurovascular structures by suction tips. Mostly, the pressure control valve of the central or portable suction machine is set to lower settings by OR personnel when dissection instead of tissue removal is done during microneurosurgery. There are sufficient literatures available, which highlight the need of control device for suction pressure, in addition to thumb control and cottonoids.,,,,,, Inadvertent closure of thumb-hole of the suction tip by the surgeon or tissue/bone fragments may lead to neurovascular trauma.,, Force of negative suction pressure can be best felt by the neurosurgeon himself and, therefore, ideally it should be under his control. Shalit  had proposed a simple suction control valve, common in principle of air leak, which too appear simple and can be controlled by the surgeon and has a total of four components as opposed to two components of our SPCV. There is only one report of suction control valve in the surgical field, which can be manipulated by the surgeon or the assistant. Other commercially available design costs more than 700 USD. SPCV is an inexpensive and simple tool and can be used, as an adjunct to the existing thumb control by the neurosurgeons working in the settings of scarce resources.
In senior author's experience, most of the microneurosurgical dissections can be done by opening the Si for 3 − 5 mm without using cotton patties, though it may change with different OR settings due to change in length and diameters of the suction tubes and diameters of the lumens of the connections in the suction systems. It can also obviate the need to use cotton patties in the narrow deep neurosurgical corridor, which hinder the surgeons view during microdissection.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
| » References|| |
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[Figure 1], [Figure 2], [Figure 3]