Patient Safety: Case Report
The purported advantages of newer electronically controlled tables, such as the Jackson Spinal Table 1 (Orthopedic Systems, Union City, CA), include ease of positioning, particularly for obese patients.1 In the prone position, the protuberant abdomen hangs freely, preventing abdominal compression.2 The patient can be turned between prone and supine positions in one motion by push of a button, thereby eliminating the risk of patient movement in a scenario of an unstable spine during combined anterior and posterior surgery. When the Wilson frame is used with the Jackson table, the frame provides abdominal and thoracic support.1 We encountered a serious hazard with the Jackson Spinal Table when a Wilson frame was used, exposing the patient to potentially serious injury.
An obese patient scheduled for L5-S1 spinal fusion with instrumentation was placed after general anesthesia induction in the prone position on a Wilson frame (Model #5319, Orthopedic Systems Incorporated), supported by a Jackson table (Model #5943, OSI). After full side-to-side frame opening, the abdomen, breasts, and upper extremities appeared to be in proper position, and the frame was then cranked maximally to flex the lumbar spine. A locking cloth safety belt was applied circumferentially around both the Jackson table and the patient at the mid-thigh level. The indicator lights on the bed were lit, confirming the rotational locked status.
When a slight axial rotational adjustment was attempted in order to rotate the table to a perfectly neutral position, the table became acutely loose and rapidly tilted vertically, causing the patient to drop to the floor. The patient's vital signs remained within normal limits, and neither the endotracheal tube, nor the IV indwelling catheters became dislodged. A large sub-galeal hematoma was readily apparent. Emergent computed tomography scanning showed no neurological injury, and the patient was then easily awakened.
The devices were immediately sequestered for inspection. A root cause analysis meeting to examine this event included those present during this event, as well as surgeons, anesthesiologists, and operating room nurses generally involved in spine surgery. It was determined that a failure of the locking mechanism caused the incident. The 180° rotational lock had been positioned properly before placement of the patient on the table; however, the added weight of the patient caused the table to unlock, such that when the rotation button was pushed, the table abruptly rotated and caused the patient to fall.
To determine if this problem had been encountered previously, we reviewed the Food and Drug Administration (FDA) Manufacturer and User Facility Device Experience database maintained by the Center for Devices and Radiological Health.3 Our experience was subsequently communicated to both the FDA and OSI, the table manufacturer.
The FDA database contained three prior serious incidents of table failure remarkably similar to ours (Table). All reports involved the OSI Jackson table model #5892 or the newer model #5943. Database reports were filed between August 2003 and April 2006. In all four incidents that included the current report, the table unexpectedly and suddenly either tilted to the side or flipped 180°, allowing the patient to fall off. One patient sustained a scalp laceration and soft tissue injury to the rib cage. Table failure and movement were traced to improper deactivation of the locking mechanism.
The lock indicator lights and the locking crank can appear ambiguous. The crank's arrowhead shape and the accompanying markings can lead one to erroneously conclude that the crank is a pointer, although it is not intended to be so. The rotational lock is in the “on” position only when the light is lit, however, regardless of the direction to which the crank points (Figs. 1 and 2).
It is common, particularly in microendoscopic spine surgery due to the need for frequent fluoroscopic guidance, to place a Wilson frame on a Jackson table. However, the resulting high center of gravity of patients renders it difficult to adequately and safely secure them to the bed. The Wilson frame further increases the risk because of the additional height above the bed at which the patient's center of gravity rests, especially during rotation, as seen in our case. Our department had a formal quality improvement meeting highlighting the potential for these problems. A laminated card with clearly elucidated instructions of use has been conspicuously secured to the head of the table as a reminder for all its users.
Familiarity with intricacies of specialized operating room equipment and the pitfalls associated with the use of this equipment are necessary for all anesthesia personnel involved. Copies of use instructions can be placed on equipment and need to be explicit and accessible to staff. Attention to these safety maneuvers may improve patient care in highly specialized surgery.
1. Orthopedic Systems Incorporated, Jackson Spinal Table Product Description. Union City, CA, June 2005
© 2009 International Anesthesia Research Society
2. Park CK. The effect of patient positioning on intraabdominal pressure and blood loss in spinal surgery. Anesth Analg 2000;91:552–7