Real‐time measurement of needle forces and acute pressure changes during intravitreal injections

Christensen, Logan; Cerda, Ashlee M.; Olson, Jeffrey L.

doi:10.1111/ceo.12963

Cited by 8 publications

(9 citation statements)

References 38 publications

(73 reference statements)

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“…3a) Figure 2c. In comparison with existing IOP data [27], Figure 2d illustrates the consistency between the presented function and the existing data.…”

Section: Cannula and Trocar Insertionsupporting

confidence: 58%

“…In all studies published so far, resulting IOP values were often determined for single steps of a specific surgical procedure [1,11,28], and the authors observed a strong surgeon-dependent correlation. Christensen et al [27] investigated the IOP resulting from insertions of 19-to 32-G needles and referenced the applied force. A correlation between the force induced and the resulting pressure is always dependent on the geometry of the instrument and the contact surface.…”

Section: Discussionmentioning

confidence: 99%

“…This should be borne in mind when performing vitrectomy after perforating keratoplasty or penetrating/open globe injuries. In these cases, smaller incisions (25,27, or 29 G) should be considered. Our results of IOP rises in cryocoagulation support the clinical experience, that predamaged corneal epithelium can decompensate during cryotherapy.…”

Section: Discussionmentioning

confidence: 99%

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Short-Term Intraocular Pressure Rise during Locally Induced Force by Ophthalmologic Surgery Applications

et al. 2018

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Purpose: Surgical or diagnostic procedures are often accompanied by a short-term increase in intraocular pressure (IOP). A short-term increase in IOP can occur during refractive procedures, vitreoretinal surgery, transillumination, photocoagulation, or cryocoagulation. A porcine eye model was chosen (n = 89) to compile comparable study data and to de termine correlations between the force induced and the resulting intraocular pressure while excluding the effect of surgeons. Methods: The IOP was measured in the anterior chamber. IOP changes were induced by applying an external force and measured when using a cannula, trocar, and cryocoagulation (n = 32), and correlations between force and resulting IOP were assessed (n = 57). Results: A correlation was noted between the force induced and the IOP increase, which showed a linear dependency. The insertion of a 29-G cannula caused a mean ΔIOP value of 49.1 ± 2.9 mm Hg and an external force of 0.76 N, and that of a 23-G trocar 344.4 ± 5.9 mm Hg and 6.09 N, respectively. The rise in IOP during a simulated cryocoagulation reached values between 57.3 ± 14.8 mm Hg (cryoprobe tip diameter: 0.9 mm) and 130.3 ± 2.9 mm Hg (cryoprobe tip diameter: 7.0 mm). Conclusion: The values of the forces applied can be converted into the resulting IOP based on the specific action. Surgical or diagnostic procedures should, therefore, be evaluated with regard to preexisting pathologies, such as glaucoma.

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“…3a) Figure 2c. In comparison with existing IOP data [27], Figure 2d illustrates the consistency between the presented function and the existing data.…”

Section: Cannula and Trocar Insertionsupporting

confidence: 58%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

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Short-Term Intraocular Pressure Rise during Locally Induced Force by Ophthalmologic Surgery Applications

et al. 2018

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“…The 30- and 32-gauge needles require the same force to penetrate scleral tissue (440 and 450 kPa); therefore, the perceived differences in pain are unlikely to be due to an increased pressure required to break the skin. 9…”

Section: Discussionmentioning

confidence: 99%

A Study to Examine the Effect of Needle Gauge on Pain Perception in Patients Receiving Treatment With Botulinum Toxin in 2 Different Anatomical Areas

Hollingsworth¹,

Brown

2020

Am J Cosmet Surg

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Botulinum toxin injection for treatment of rhytids is the commonest cosmetic intervention undertaken worldwide. It requires re-treatment at 3-month intervals for the effect to remain. Consequently, patient comfort is paramount in order for the procedure to remain acceptable. Intuitively, patients expect that smaller needles will be less painful, and this study examines the pain caused by needles of 2 gauges (31 and 32) when administering botulinum toxin in 2 anatomical areas. Patients were randomized into having the left or right side of their face treated with either a 31- or 32-gauge needle during botulinum toxin administration. Participants were asked to determine whether the left- or right-side treatment was most painful. The study was repeated in the glabellar and paraorbital regions. A total of 103 participants entered the study; 98 had the glabellar region treated and 76 the crow’s feet, and 72 patients had both regions treated. For the glabellar region, the smaller 32-gauge needle was significantly more painful than the larger 31-gauge needle ( P < .01). There was no difference in patient’s pain perception between gauges of needle when treating the crow’s feet area ( P = .9). The 31-gauge needles produce significantly less pain than smaller 32-gauge needles when treating the glabellar region with botulinum toxin, but not in the periorbital region. We propose that this is due to differences in fascial adherence between the 2 areas. Consequently, we would recommend administering botulinum toxin with a 31-gauge needle in all areas.

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“…The maximum load was chosen based on medical experience and values expected from the literature [ 17 ]. The test speed was adjusted based on puncture force tests already carried out [ 18 ].…”

Section: Methodsmentioning

confidence: 99%

Needle penetration test - qualifying examination of 3D printable silicones for vascular models in surgical practice

et al. 2021

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Background During cardiogenic shock blood circulation is minimal in the human body and does not suffice to survive. The extracorporeal life support system (ECLS) acts as a miniature heart-lung-machine that can be temporarily implanted over major vessels e.g. at the groin of the patient to bridge cardiogenic shock. To perform this procedure in an emergency, a proper training model is desirable. Therefore, a 3-dimensional-printable (3D) material must be found that mimics large vessel needle penetration properties. A suitable test bench for material comparison is desirable. Methods A test setup was built, which simulated the clinically relevant wall tension in specimens. The principle was derived from an existing standardized needle penetration test. After design, the setup was fabricated by means of 3D printing and mounted onto an universal testing machine. For testing the setup, a 3D printable polymer with low Shore A hardness and porcine aorta were used. The evaluation was made by comparing the curves of the penetration force to the standardized test considering the expected differences. Results 3D printing proved to be suitable for manufacturing the test setup, which finally was able to mimic wall tension as if under blood pressure and penetration angle. The force displacement diagrams showed the expected curves and allowed a conclusion to the mechanical properties of the materials. Although the materials forces deviated between the porcine aorta and the Agilus30 polymer, the graphs showed similar but still characteristic curves. Conclusions The test bench provided the expected results and was able to show the differences between the two materials. To improve the setup, limitations has been discussed and changes can be implemented without complications.

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Real‐time measurement of needle forces and acute pressure changes during intravitreal injections

Cited by 8 publications

References 38 publications

Short-Term Intraocular Pressure Rise during Locally Induced Force by Ophthalmologic Surgery Applications

Short-Term Intraocular Pressure Rise during Locally Induced Force by Ophthalmologic Surgery Applications

A Study to Examine the Effect of Needle Gauge on Pain Perception in Patients Receiving Treatment With Botulinum Toxin in 2 Different Anatomical Areas

Needle penetration test - qualifying examination of 3D printable silicones for vascular models in surgical practice

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