Power morcellation for uterine fibroids: What you need to know
What you need to know
Tissue morcellation is by no means a new concept in laparoscopic surgery, but recent concerns regarding open power morcellation in gynecologic procedures have called the practice into question.1 A hand-activated device for laparoscopic tissue removal was developed as early as 1973, and by 1993, the Steiner electromechanical morcellator was introduced.2,3
The advent of electromechanical morcellation allowed for marked improvements in ease and speed of specimen retrieval with minimally invasive approaches.4,5 As the field of minimally invasive gynecologic surgery has evolved to encompass increasingly challenging procedures, a number of power morcellation devices have been marketed to allow removal of large pathology via small incisions and avoid the morbidity associated with laparotomy. However, this innovation is not without risks, including potential for intraoperative injury and risk of seeding of cellular tissue during the morcellation process.
Gynecologic surgeons should give consideration to the balance of benefit and harm that accompanies laparoscopic tissue morcellation, in addition to exploring surgical alternatives and methods to mitigate complications.
Risks associated with morcellation
Rates of visceral and vascular injury associated with electromechanical morcellation devices are difficult to quantify due to limited reporting. A recent systematic review of all published articles as well as the FDA device database identified 55 morcellator-related injuries during gynecologic (hysterectomy, myomectomy) and non-gynecologic (nephrectomy, splenectomy) procedures.6 Vascular and bowel injuries were listed as the most common complications. In this review, surgeon inexperience was the most commonly listed risk factor for injury.
Aside from the risks inherent in surgical operation of morcellation devices, there is also concern about dissemination of tissue that can occur during an open power morcellation process. Fragments of tissue that are not retrieved may result in pain, infection and serious morbidity.7,8 Intracorporeal morcellation has also been reported to result in seeding of benign9-12 or malignant tissues.13-16 The incidence of such complications is difficult to quantify; the AAGL practice guidelines for laparoscopic subtotal/supracervical hysterectomy state that uterine morcellation does not appear to increase the risk of subsequent diagnosis of endometriosis and only rarely results in leiomyomatosis.17 Reported incidence of parasitic leiomyomata following laparoscopic procedures involving morcellation has been estimated at between 0.1% and 1% based on 2 retrospective studies.11,12
Of particular concern is the risk of morcellating an unidentified malignancy, with possible resultant upstaging of disease and worsened prognosis.18-20 In a recent statement, the Society of Gynecologic Oncology estimated that fewer than 1 woman in 1000 who undergoes hysterectomy for a presumed leiomyomata will have an occult malignancy, and advocated for open communication with patients regarding this issue.21 Unlike endometrial lesions, which are characterized by more reliable risk factors, symptomatology, and screening methods, uterine leiomyosarcomas are the subject of considerable concern because they are often difficult to differentiate from benign leiomyomata preoperatively. Leiomyosarcomas also are notoriously aggressive tumors associated with poor prognosis even in the absence of tissue morcellation.
Compounding the difficulties of diagnosis is the relative rarity of uterine leiomyosarcomas; incidence in the general population is estimated at 1 in 10,000 women, or approximately 1 in 1,000 women undergoing surgery for presumed fibroids.20,22-24 Suggested clinical factors that may heighten concern for malignancy include advancing patient age and presence of new or increasing uterine mass in a postmenopausal patient. The average age at presentation is 60 years; however, leiomyosarcomas have been reported in patients as young as their mid-20s.25 The rate of uterine growth has not been demonstrated to be a reliable predictor for malignancy.24 Screening techniques for uterine sarcomas are limited, but magnetic resonance imaging (MRI), particularly diffusion-weighted, and serum samples of lactate dehydrogenase (LDH) have been suggested as potential screening methods.26,27 One small prospective study demonstrated high sensitivity and specificity with the combination of dynamic MRI and measurement of total LDH and LDH isoenzyme type 3, but the results have not been reproduced on a larger scale.27