[Computerized tomography guided biopsy in the diagnosis of neoplastic and inflammatory lesions of the pelvis].

PURPOSE: To assess the efficacy of percutaneous CT-guided biopsy in the diagnosis and therapeutic planning of neoplastic and flogistic diseases of the pelvis.

MATERIAL AND METHODS: From July 1990 to December 1999 193 patients (113 males, 80 females: mean age 49, standard deviation 16) were submitted to CT-guided percutaneous biopsy of the pelvic region; 117 biopsies (61%) were performed at iliac, pubic and ischial segments and 76 (39%) at sacral region; 107 patients were admitted to the hospital and 86 were in clinic. Needles were 8 G (4 mm), 10 to 15 cm long. Approach to pelvic lesions was performed according to the specific site. Lesions of the lateral pelvic region have always been approached through the lateral surgical incision according to Enneking. Lesions of the posterior pelvic region have always been approached by the introduction of the needle along the posterior surgical incision according to Enneking. Lesions of the anterior region have always been approached through the anterior surgical incision according to Enneking. From July 1990 to May 1997 pelvic percutaneous biopsies have been carried out with a CT Sytec 3000. From May 1997 to December 1999 the device was replaced by a High Speed CTi. The introduction of spiral CT allowed reduction of performance mean time from 45 minutes (standard deviation 15) to 30 minutes (standard deviation 10).

RESULTS: In 154 patients (80%) we observed a neoplastic, inflammatory or not classified degeneration. In 8 patients (4%) the retrieved material ended to be inadequate for a diagnosis. In 31 patients (16%) no disease was revealed at the histological examination. Such patients with negative histological examination have been kept under clinical and radiological control in the following period in order to verify the manifestation or the presence of an alteration previously not observed. On 31-3-2000 none of them had been submitted to a new percutaneous biopsy of the pelvic region. The overall mean accuracy has been 96% considering the negative patients as really negative. In 5 cases (2.6%) we have had complications represented by pain at the introduction and penetration site of the needle.

DISCUSSION AND CONCLUSIONS: The choice of the needle, the approach to the lesion and the position of the patient are conditioned by the site of the tumor, its extension, the distance skin-neoplastic disease and by the respect of the incision lines of Enneking, in order not to complicate the job of the orthopaedic surgeon spreading tumoral cells outside the chosen surgical approach. The mean time of the procedure is 30 minutes (standard deviation 10). There are no absolute contraindications to percutaneous biopsy except the suspect or the presence of an hydatideal cyst. The risks have to be compared with those correlated with alternative methods or with the more concerning risk of a missed diagnosis. Complications in the literature range from 0% to 10%, the incidence varying according to the location; pain is the most frequent complication. Altogether the most negative event, although not a true complication, is the retrieval of an inadequate sample: the only drawback of percutaneous biopsy in comparison with incisional biopsy. The accuracy rate of percutaneous biopsy varies in relation to the involved anatomical region, to the pathological process, to the experience of the user, to the amount of the retrieved tissue and to the cooperation of the patient. Our experience shows that, in selected patients, percutaneous biopsy is a virtually safe and almost painless procedure which saves the patient from a surgical procedure in regional or general anestesia as for an incisional biopsy, and allows immediate planning and scheduling of a correct therapy for primitive or secondary neoplastic lesions.