Do Arthroscopic Fluid Pumps Display True Surgical Site Pressure During Hip Arthroscopy?

Improving visualization in shoulder arthroscopy

Arthroscopic shoulder procedures are one of the most common procedures used to restore function through minimally invasive techniques. With the demand for shoulder arthroscopic procedures comes the need for safe, effective, and efficient surgery that maximizes patient outcomes while minimizing complications. Many variables contribute to visualization in shoulder arthroscopy including vascular anatomy, blood pressure control, arthroscopic pump systems, turbulence control, epinephrine, and tranexamic acid. Furthermore, patient positioning can have a dramatic effect on visualization with both the beach chair position and lateral decubitus positioning having various strengths and weaknesses depending on the intended procedure being performed. The purpose of this review is to examine the benefits and complications reported in the literature for improving visualization in shoulder arthroscopy.

Fundamentals of Arthroscopy Fluid Management and Strategies to Safely Improve Visualization

Arthroscopy has become increasingly relevant to various subspecialties within the orthopaedic surgery. From a patient safety standpoint and surgical efficiency standpoint, it is critical to know the fundamental concepts of fluid management such as those related to the fluid, pressure, and flow. A satisfactory field of view during arthroscopy can be achieved with the use of gravity-dependent or automated fluid management systems. Fluid management parameters and their physiological impact on the patient should be continuously monitored to avoid morbidity or delayed recovery. Local and systemic complications can occur from careless use of techniques that improve visualization such as tourniquet, epinephrine-diluted irrigation, and controlled hypotensive anesthesia. The purpose of this article is to review the fundamental concepts of fluid management in arthroscopy and the techniques to safely improve arthroscopic visualization.

Accuracy of arthroscopic fluid pump systems in shoulder surgery: a comparison of 3 different pump systems

BACKGROUND

Extra-articular fluid extravasation is a known complication during shoulder arthroscopy. The risk and amount of extravasation to a large degree is dependent on the fluid pressure delivered to the surgical site. Accurate measurement, knowledge, and control of the pressure delivered is thus important to surgeons, anesthetists, and the patient. The purpose of this study was to compare the pressure measurement accuracy of 3 arthroscopic fluid pumps, with 2 of them having 2 different settings.

METHODS

Twenty-five patients (n = 5 per group) undergoing shoulder arthroscopy were selected. Three different arthroscopic fluid pumps (ConMed 24K, Stryker Crossflow, Arthrex Dual Wave) were tested in 5 different operational settings (Stryker, standard and dynamic mode; ConMed, with and without TIPS; Arthrex Dual Wave). In each operation, the set pump pressures and the subsequently delivered intra-articular surgical site fluid pressures were measured by a spinal needle connected to an anesthetic standard pressure transducer attached to the anesthetic machine. Independent measures of the surgical site pressures were obtained before multiple portals were created or extravasation had occurred. Measurements were taken at the beginning of surgery.

RESULTS

Measurements of the mean intra-articular pressure were found to not be significantly different from the set pressure for the ConMed 24K with TIPS (0.98 ± 0.02-fold) and Stryker Crossflow in standard mode (0.98 ± 0.02-fold). However, actual pressure was significantly greater than the set pressure for the ConMed 24K without TIPS (by 1.30 ± 0.13-fold), Stryker Crossflow in dynamic mode (by 1.82 ± 0.08-fold), and Arthrex Dual Wave (by 2.19 ± 0.06-fold).

CONCLUSION

Independently measured intra-articular pressure can be more than double the set pressure for some arthroscopic pumps. Measuring intra-articular pressure can thus aid in adjusting the set pressure. This could minimize the risk of intraoperative complications.

Carbon dioxide gas endoscopy of the deep gluteal space

The treatment of hip and pelvic pain associated with abnormalities of the deep gluteal space has evolved and increasingly involves endoscopic techniques with a saline expansion medium. This investigation presents a surgical technique utilizing carbon dioxide as the insufflation medium for deep gluteal space endoscopy in 17 cadaveric hips. This technique was successful in 94% (16/17) of the hips, allowing for visualization of the sciatic nerve, posterior femoral cutaneous nerve, pudendal nerve, branch of the inferior gluteal artery crossing the sciatic nerve, piriformis muscle, hamstring tendon origin, and lesser trochanter. Our experience suggests that gas expansion presents several advantages over fluid expansion.

Gravity Fluid Flow More Accurately Reflects Joint Fluid Pressure Compared With Commercial Peristaltic Pump Systems in a Cadaveric Model

PURPOSE

To evaluate intra-articular fluid pressures and joint compliance generated by fluid management systems on cadaveric shoulders and knees under simulated arthroscopic conditions, and to compare joint compliance between knee and shoulder specimens.

METHODS

Intra-articular pressures of 5 cadaver shoulders and 5 knees were recorded for 4 arthroscopic pumps (Stryker FloControl, Stryker CrossFlow, Arthrex DualWave, DePuy Mitek FMS Duo) and a gravity feed system. Each specimen was tested 6 times with a pressure transducer for 2 minutes at 0, 25%, and 50% suction. The average pressures were analyzed with 1-way analysis of variance and Tukey's honestly significant difference tests (P < .05).

RESULTS

At all suction levels, all pumps exhibited significantly greater pressure than gravity feed (P = .001 to P < .001). At both 25% and 50% suction, FloControl displayed significantly greater pressures (P_max 160.44 mm Hg) than the other pumps or gravity feed (P_max 46.9 mm Hg). CrossFlow had the lowest net percentage error (36.8%, 18.4 mm Hg) when compared with the standard pressure of 50 mm Hg, followed by gravity feed. All pumps had large initial overshoot (ie, P_initial CrossFlow 99.4 mm Hg) followed by settling time, whereas gravity feed did not (P_initial 55.2 mm Hg).

CONCLUSIONS

Gravity feed is an accurate, reliable delivery method for arthroscopic fluid with minimal overshoot and lower intra-articular pressure ranges than commercial pump systems. There was no evidence of plastic deformation of the joint capsule, because capsular compliance increased linearly in both knee and shoulder specimens throughout testing within the established safe range of intra-articular pressures.

CLINICAL RELEVANCE

Arthroscopic flow management systems produce maximal and overshoot pressures that are not seen with gravity flow. Surgeons should understand intra-articular pressure and fluid delivery behavior during shoulder and knee arthroscopy to adapt to the variability and higher maximal pressures when using pump systems. Maintaining appropriate pressure could prevent fluid extravasation and possible neuromuscular dysfunction.

Editorial Commentary: To Pump or Not to Pump? Gravity Versus Fluid Pumps for Shoulder and Knee Arthroscopy

Recent studies and our clinical experience have supported the safety and efficacy of various arthroscopic pumps for use in practice. Different pump designs are to be used in different ways. Although gravity flow can lead to constant low pressure in a cadaveric knee or shoulder, it may not provide optimal visualization or performance to best complete your surgical procedure. To take the best care of our patients, understanding basic fluid pump design and understanding what pump design resides in your operating room is important for all practicing arthroscopists.

The influence of radio frequency ablation on intra-articular fluid temperature in the ankle joint - a cadaver study

Background

Radio frequency ablation devices have found a widespread application in arthroscopic surgery. However, recent publications report about elevated temperatures, which may cause damage to the capsular tissue and especially to chondrocytes. The purpose of this study was the investigation of the maximum temperatures that occur in the ankle joint with the use of a commercially available radio frequency ablation device.

Methods

Six formalin-fixed cadaver ankle specimens were used for this study. The radio frequency device was applied for 120 s to remove tissue. Intra-articular temperatures were logged every second for 120 s at a distance of 3, 5 and 10 mm from the tip of the radio frequency device. The irrigation fluid flow was controlled by setting the inflow pressure to 10 mmHg, 25 mmHg, 50 mmHg and 100 mmHg, respectively. The controller unit voltage setting was set to 1, 5 and 9.

Results

Maximum temperatures exceeding 50 °C/122 °F were observed for all combinations of parameters, except for those with a pressure of 100 mmHg pressure. The main critical variable is the pressure setting, which is highly significant. The controller unit voltage setting showed no effect on the temperature measurements. The highest temperature was 102.7 °C/215.6 °F measured for an irrigation flow of 10 mmHg. The shortest time span to exceed 50 °C/122 °F was 3 s.

Conclusion

In order to avoid temperatures exceeding 50 °C/122 °F in the use of radio frequency devices in arthroscopic surgeries of the ankle joint, it is recommended to use a high irrigation flow by setting the pressure difference across the ankle joint as high as feasible. Even short intervals of a low irrigation flow may lead to critical temperatures above 50 °C/122 °F.

Level of Evidence

Level II, diagnostic study.

Editorial Commentary: Hip Arthroscopy Pump Pressure Must Be Managed and Monitored

Fluid pump management is essential for successful hip arthroscopy. Low pressures can lead to poor visualization. High pressures can lead to fluid extravasation and complications. Fluid extravasation during hip arthroscopy can lead to intra-abdominal compartment syndrome, which can be life-threatening. Risk factors for extravasation included higher pump pressures and iliopsoas tenotomy. By accurately measuring pump pressures, minimizing the necessary pressure, avoiding excessive capsulotomies, performing iliopsoas tenotomy only if needed and performing it at the end of the operation, and monitoring the patient for abdominal distention and hypothermia, complications can be minimized.