Detection rates of missing microsurgical needles using intra-operative imaging

Management of the intraoperative loss of microsurgical needles: A literature review and clinical survey

Data on the incidence, management, and consequences of retained microsurgical needles in plastic and reconstructive surgery remains sparse. Research suggests that a mobile C-arm x-ray has a low detection rate for needles of size 8-0 or smaller. By means of a literature review, and survey, we aimed to investigate the current practice employed in the event of the intraoperative loss of a microsurgical needle. A literature review was conducted investigating the incidence, current management strategies, and consequences of retained microsurgical needles. This informed the questions included in a survey investigating management strategies employed in the intra-operative loss of a microsurgical needle. Results from the literature review show an overall low detection rate of microsurgical needles on imaging. Of the forty responders who completed the survey, 80% did not use a mobile C-arm x-ray to locate a missing microsurgical needle. Of the 20% that had done so, x-ray had been unsuccessful in locating the needle in all cases. Portable x-ray has a definite role to play in locating needles of size 7-0 or larger. This study suggests that suture needles of size 8-0 or smaller cannot be reliably detected on x-ray. Regarding management of this event, one should consider the risk of harm to the patient if retained, against the risk of searching for the needle. Based on the results of this work as well as existing published data, we advise against obtaining intra-operative x-rays in the event of a lost needle size 8-0 and above. Appropriate documentation should be completed.

Assessment of x-ray efficacy for intraoperative microneedle retrieval using a cadaveric model

INTRODUCTION

Institutional protocols often mandate the use of x-rays when a microneedle is lost intraoperatively. Although x-rays can reliably show a macroneedle, the benefit of x-rays in detecting microneedles in human tissues has not been established as available data on this topic are investigated in anthropometric models. The current study aims to evaluate whether x-rays can reliably detect retained microneedles in a human cadaveric model. We hypothesize that microneedles would be detected at a significantly lower rate than macroneedles by x-ray in human tissues.

MATERIALS AND METHODS

Needles ranging from 4-0 to 10-0 were placed randomly throughout a cadaveric hand and foot. Each tissue sample was x-rayed using a Fexitron X-Ray machine, taking both anteroposterior and lateral views. A total of six x-ray images were then evaluated by 11 radiologists, independently. The radiologists circled over the area where they visualized a needle. The accuracy of detecting macroneedles (size 4-0 to 7-0) was compared with that of microneedles (size 8-0 to 10-0) using a chi-square test.

RESULTS

The overall detection rate for the microneedles was significantly lower than the detection rate for macroneedles (13.5% vs 88.8%, p < .01). When subcategorized between the hand and the foot, the detection rate for microneedles was also significantly lower than the rate for macroneedles (hand: 7.6% for microneedles, 93.2% for macroneedles, p < .01; foot: 19.5% for microneedles, 84.4% for macroneedles, p < .01). The detection rate, in general, significantly decreased as the sizes of needles became smaller (7-0:70.5%, 8-0:18.2%, 9-0:16.7%, 10-0:2.3%, p < .01).

CONCLUSION

X-rays, while useful in detecting macroneedles, had a significantly lower rate of detecting microneedles in a cadaveric model. The routine use of x-rays for a lost microneedle may not be beneficial. Further investigation with fresh tissue and similar intraoperative x-ray systems is warranted to corroborate and support these findings.

Microsurgical Needle Retention Does Not Cause Pain or Neurovascular Injury in a Rat Model

Approximately 20% of retained foreign bodies are surgical needles. Retained macro-needles may become symptomatic, but the effect of microsurgical needles is uncertain. We present the first animal model to simulate microsurgical needle retention. Given a lack of reported adverse outcomes associated with macro-needles and a smaller cutting area of microsurgical needles, we hypothesized that microsurgical needles in rats would not cause changes in health or neurovascular compromise.

Methods

Male Sprague-Dawley rats (x̄ weight: 288.9 g) were implanted with a single, 9.0 needle (n = 8) or 8.0 needle (n = 8) orthogonal to the right femoral vessels and sutured in place. A control group (n = 8) underwent sham surgery. Weekly, a cumulative health score evaluating body weight, body condition score, physical appearance, and behavior for each rat was determined. Infrared thermography (°C, FLIR one) of each hindlimb and the difference was obtained on postoperative days 15, 30, 60, and 90. On day 90, animals were euthanatized, hindlimbs were imaged via fluoroscopy, and needles were explanted.

Results

The mean, cumulative health score for all cohorts at each weekly timepoint was 0. The mean temperature difference was not significantly different on postoperative days 15 (P = 0.54), 30 (P = 0.97), 60 (P = 0.29), or 90 (P = 0.09). In seven of eight rats, 8.0 needles were recovered and visualized on fluoroscopy. In six of eight rats, 9.0 needles were recovered, but 0/8 needles were visualized on fluoroscopy.

Conclusions

Microsurgical needle retention near neurovascular structures may be benign, and imaging for needles smaller than 8.0 may be futile. Further studies should explore microsurgical needle retention potentially through larger animal models.