Электронный научный журнал

Современные проблемы науки и образования. Хирургия

ISSN 2686-9101

Fig. 4. Histological structure of tumors in Group II

The analysis of the frequency of surgical treatment showed that the first surgery was performed only in 3 cases (14.3%) in Group I, and in 7 cases (43.8%) in Group II. In the majority of cases, by the time of hospitalization to the clinic, patients already underwent several non-radical surgical interventions including biopsy and partial resection (Table 1).

Table 1.

Number of non-radical surgical invasions that patients underwent by the time of hospitalization to the clinic

In the group of patients with malignant neoplasms, radical types of en bloc resection of the petrous pyramid were performed (Table 2). This is explained by the necessity of complete resection of the tumor according to the principles of ablastics, which requires a safe formation of a block of tissues by the healthy borderline with its further mobilization and resection. Apart from intra-operational control, the evaluation of the radicality of en bloc resection of the petrous pyramid was performed using control post-operational CT images of the brain. The authors relied on the generally accepted criteria of the radicality of resection described in the published literature [6].

Table 2

The ratio of the volumes of pyramid resection in Group I

In the group of patients with benign tumors, en bloc resection of the petrous pyramid was performed primarily as an element of surgical access, which is confirmed by a lower number of radical en bloc resections in comparison with Group I (Table 3).

Table 3

The ratio of the volume of pyramid resection in Group II

In the present study, all the patients underwent different types of reconstruction of post-resection defects (Table 4). The necessity of this procedure is explained by the prevention of the formation of “dead space” in the area of intervention, which can be associated with an increased risk of post-operational complications that include inflammation and wound infection, liquor accumulation, and liquorrhea (in cases of dura mater defects).

Table 4

Types of reconstruction of post-resection defects

Note: TDF – thoracodorsal flap

En bloc resection of the petrous pyramid in the required volume allowed the surgeons to perform radical tumor resection in the majority of patients with malignant neoplasms (Table 5).

Table 5

Radicality of tumor resection in Group I

Total tumor resection was considered successful when it was resected in one block within the borders of healthy tissues. This method is called clean margin resection. Such result was registered in 15 patients (71.4%) from Group I. When it was not possible technically to resect the tumor completely because of the involvement of vital vessels and neural structures in the process, the volume of resection was limited to subtotal resection (5 patients, 23.8%). In 1 case, the tumor location and previous operations did not allow the surgeons to perform the resection in the required volume.

The rate of radicality of tumor resection in Group II was lower (Table 6). This is explained by the balance between the volume of tumor resection and the decrease in risk of the post-operative deficit because, according to the published data, it is possible to perform non-radical tumor resection without a significant influence on the outcome.

Table 6

Radicality of resection of tumors in Group II

To evaluate the dynamics of the patients’ condition by the Karnofsky scale, the authors chose two endpoints: hospital admission and discharge. The dynamics of this data is presented in Figures 5 and 6.

Fig. 5. Dynamics of the condition of patients by the Karnofsky scale in Group I (p<0.05)

Fig. 6. Dynamics of the condition of patients by the Karnofsky scale in Group II (p<0.05)

The total amount of complications in groups is presented in Table 7. It is important to note that in Group I, some local and general complications were observed in the same patient (4 patients, 19%).

Table 7

The total rate of complications in Groups

A high rate of post-operative complications in Group I is explained by several factors: the initially relatively severe condition of a patient after previous operations in the anamnesis with further radiotherapy (18 cases, 85.7%), a vast volume of post-resection cavities, and application of complicated reconstructive techniques.

The analysis of complications by groups revealed the correlation between the increase in the rate of local complications (52.4%) and the increase in the rate of using TDF for closing the post-operative defect (71.4%) in patients with malignant tumors (Table 8). On the other hand, the reconstruction of local tissues (75%) in Group II correlated with the decrease in the rate of local complications (18.8%).

Table 8

Structure of complications

It should be mentioned that in the present study, the authors did not consider the development of the paresis of mimic structure on the side of operation after subtotal and total en bloc resection of the petrous pyramid as a complication because such manipulations are inevitably associated with the transection of the facial nerve.

The lethal outcome was registered in 3 cases (8%) in Group I.

DISCUSSION

Presently, total radical resection with or without further adjuvant therapy is considered to be a generally-accepted method of treatment for patients with tumors of lateral skull base [7; 8]. An interdisciplinary approach to this surgical problem allows the specialists to achieve satisfactory results with a relatively low level of morbidity or lethality.

Adequate reconstruction of the post-operative defect is an obligatory component of a successful outcome of the treatment with en bloc resection [6; 9]. Apart from sealing the post-resection cavity, in order to prevent the formation of “dead space”, the chosen method of reconstruction should provide maximum aesthetic qualities, which potentially influences the social adaptation of patients after the surgery.

In the present study, the rate of complications and lethality was 54.1% and 8%, respectively. The values of these parameters agree with the published data [1; 10-12].

The authors used a differential approach to en bloc resection of the petrous pyramid depending on the aim of the surgery. For patients with a malignant tumor, this method was used for the formation of a block of tissues that included the complete tumor node. Its clean margin resection agreed with the accepted practice in oncology. In the majority of patients with benign tumors, en bloc resection of the petrous pyramid was used as surgical access for adequate visualization and further mobilization of the tumor with the control of neural and vascular structures.

The present study had some limitations. First, the obtained results cannot be used as grounds for the modification of the existing recommendations because of small sampling, which is associated with a rare occurrence of this pathology and strict requirements on the intracranial spread of tumor as the study entry criterion. Second, a relatively high rate of morbidity is explained by a severe condition of patients by the time of hospitalization.

CONCLUSIONS.

The performed analysis of the experience of en bloc resection of the petrous pyramid in the treatment of patients with tumors in the lateral skull base showed that the specified technique can be considered safe and efficient. The existing methods of en bloc resection and post-operative reconstruction require further studies and improvement.

FINANCIAL SUPPORT AND SPONSORSHIP
Nil.
CONFLICTS OF INTEREST
The authors declare no conflict of interest