RU2781743C1 - Method for retrosigmoid retrocondylar approach to aneurysms of the posterior inferior cerebellar artery in the acute haemorrhaging period - Google Patents

Abstract

FIELD: medicine.

SUBSTANCE: invention relates to medicine, namely to neurosurgery. A retrosigmoid retrocondylar approach to aneurysms of the posterior inferior cerebellar artery is made. The posterior ring of the great occipital foramen is additionally resected herein up to the occipital condyle.

EFFECT: method allows for the approach to aneurysms of the posterior inferior cerebellar artery in the acute haemorrhaging period, early proximal control, minimised traction of the cerebellar hemisphere, improved imaging of the structures of the posterior cranial fossa, sanitation of the fourth ventricle from blood clots and restored cerebrospinal fluid circulation, effective intervention, lower number of associated intraoperative and postoperative complications, and ensured good recovery of patients with aneurysms of the posterior inferior cerebellar artery in the acute haemorrhaging period.

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Description

The invention relates to medicine, namely to neurosurgery.

Aneurysms of the posterior inferior cerebellar artery (PICA) are rare and account for approximately 3% of all intracranial aneurysms [SalcmanM, RigamontiD, NumaguchiI, SadatoN. Aneurysm soft heposterior inferior cerebellar artery-vertebralartery complex: variationsonatheme. neurosurgery. -1990. - 27. - P. 12-20]. Microsurgical treatment of PICA aneurysms, given their proximity to the caudal group of cranial nerves and the brainstem, is a complex and unresolved problem. Endovascular intervention may be accompanied by a high incidence of aneurysm revascularization [NussbaumE. Video atlas of intracranial aneurysm surgery. Thieme. - 2013. - p. 91]. Therefore, the search for a safe and effective surgical approach that will provide total exclusion of the aneurysm is an urgent problem.

In the vast majority of cases, PICA aneurysms are manifested by subarachnoid hemorrhage (SAH). Microsurgical treatment includes different approaches depending on the projection of the aneurysmal sac, the size of the aneurysm, the presence of hemorrhage, symptoms of increased intracranial pressure. Planning for an effective and safe approach can be identified with the outcome of surgical treatment.

A known method of surgical treatment of PICA aneurysms using extended lateral suboccipital craniotomy, resection of the squamous occipital bone and laminectomy of the C1 vertebra. A potential disadvantage of this approach is the unreasonably large size of the trepanation with significant concomitant traumatization, which, in turn, may increase the risk of developing pyoinflammatory complications and the formation of epidural hematomas and cerebrospinal fluid cushions. The surgical route itself is deep and limited. The proximity of work with the caudal group of cranial nerves lead to the development of bulbar syndrome, prolongation of mechanical ventilation and adverse outcomes [DrakeC, PeerlessS, HemesniemiJ. Surgery of Vertebrobasilaraneurysms. Springer. - 1995. - 329 p.] [HerosRC. Lateral suboccipital approach for vertebral and vertebrobasilar circulation artery lesions. JNeurosurgery. - 1986. - 64. - p. 559-562].

A known method of surgical treatment of aneurysms of the PICA from the traditional retrosigmoid access, which is characterized by resection of the occipital bone medial to the sigmoid sinus [TroudeL, BernardF, SuEC, RochePH. The modified retrosigmoid approach: a how I do it. Acta Neurochirurgica. - 2019. - 161. - p. 417-423]. However, the disadvantage of this approach is the lack of resection of the posterior part of the margin of the foramen magnum, which reduces the working space for manipulation of microinstruments, excludes the possibility of early proximal control of the vertebral artery, and complicates manipulations in the area of the 4th ventricle, namely, removal of clots and restoration of CSF circulation.

The method of surgical treatment of PICA aneurysms using retrosigmoid access was chosen as the closest analogue. In this type of access, the skin incision is made retromastoidally 1-1.5 cm away from the hairline in the behind-the-ear region, 7-8 cm long. Next, 2 retractors are installed. The dissection of the sternocleidomastoid muscle is carried out using monopolar coagulation. During the dissection, the occipital artery is identified and transected. As a rule, at this stage, bleeding from the emissary vein is observed, which is stopped with the help of wax. Using a high-speed burr and a craniotomy, a traditional craniotomy 4×4 cm is performed, the upper border of the projection is the transverse sinus. The lateral edge of the trepanation is the border that is adjacent to the sigmoid sinus. The large occipital foramen is not resected. Later, the dura mater is opened arcuately with the base to the sigmoid sinus and the transition to the main stage of the operation is carried out. Next, an approach is made to the large cerebral cistern for relaxation of the cerebellar hemisphere. The caudal group of nerves is identified. Nerve dissection is performed. The PICA and the vertebral artery are exposed. After that, the aneurysm neck is dissected and clipped. Upon completion of the main stage of the operation, the dura mater is tightly sutured, the bone is set in place, fixed with a titanium fixator, soft tissues are sutured in layers [TroudeL, BernardF, SuEC, RochePH. Themodifiedretrosigmoidapproach: ahowIdoit. Acta Neurochirurgica. - 2019. - 161. - p. 417-423] [Quinones-Hinojosa A, Chang EF, Lawton MT The extended retrosigmoid approach: an alternative to radical cranial base approaches for posterior fossa lesions. neurosurgery. - 2006. - 58. - p. ONS-208-ONS-214, discussion ONS-214].

However, certain difficulties in using the traditional retrosigmoid approach may arise due to the limited space in the acute period of hemorrhage. As a rule, after opening the dura mater, the cerebellar hemisphere begins to prolapse into a trepanation defect. To relax the cerebellum, it is necessary to make quick access to the cisterns, but this manipulation is difficult due to the presence of a bone barrier at the edge of the foramen magnum. Therefore, the neurosurgeon is forced to carry out aggressive traction of the cerebellar hemisphere, which can lead to premature rupture of the aneurysm and difficult-to-control bleeding. An important disadvantage of this approach is also the lack of early proximal control of the vertebral artery, which is the gold standard in aneurysm microsurgery. Often, rupture of aneurysms of the PICA leads to occlusive hydrocephalus against the background of blockade of the foramen of Magendie, and the neurosurgeon must make quick access to the 4th ventricle, which also causes difficulties in the classical retrosigmoid approach due to the lack of surgical angles and free space. The consequences of the above intraoperative complications directly affect the disability and mortality after surgical interventions. The period of stay of patients in intensive care, on a ventilator is prolonged, the risk of neurological deterioration against the background of cerebellar traction, damage to the cranial nerves, occlusive hydrocephalus increases [SongJ, ParkJE, ChungJ, LimYC, ShinYS. Treatment strategies of ruptured posterior inferior cerebellar artery aneurysm according to its segment. Surg Neurol Int. - 2017. - 8. - 155] [Hudgins RJ, Day AL, Quisling RG, Rhoton AL, Sypert GW, Garcia-Bengochea F. Aneurysms of the posterior inferior cerebellar artery. A clinical and anatomical analysis. J Neurosurg. 1983; 58:381-387].

In this regard, a modified retrosigmoid retrocondylar approach to aneurysms of the posterior inferior cerebellar artery in the acute period of hemorrhage is proposed.

The objectives of this invention are: improving the results of treatment of patients with aneurysms of the posterior inferior cerebellar artery; reducing the risk of developing complications associated with a lack of proximal control of the vertebral artery, excessive traction of the cerebellum, limiting the necessary actions to sanitize the 4th ventricle from blood clots and resolve occlusive hydrocephalus.

The problem is solved in the following way. Before surgery, all patients underwent a standard examination plan. All operations were performed according to emergency indications after verification of the diagnosis. The patient in the operating room was laid on his side, his head was fixed in a Mayfield-type bracket. The patient's head bends downward and forward with control of the jugular veins and the absence of their compression. The shoulder on the access side is brought down with the help of special belts. Thus, access to the surgical area is not blocked by the shoulder. The planned incision site in the behind-the-ear region is infiltrated with an anesthetic. Processing of the surgical field is carried out with iodine antiseptics. The projection of the transverse and sigmoid access is preliminarily marked, the mastoid process is palpated. A slightly arched skin incision of 9-10 cm is performed in the behind-the-ear region, retromastoidally within the scalp. Monopolar coagulation dissects the periosteum and sternocleidomastoid muscle. Bleeding from the emissary vein is stopped with wax. Next, the asterion point of convergence of the lambdoid, occipital-mastoid, and parietal-mastoid sutures was identified. The burr hole was placed in the area of the asterion using a cranioperforator. The internal plasty in the burr hole was additionally resected with pistol cutters and venous sinuses were identified: which have a characteristic blue tint. Then, using a craniotomy, a classic retrosigmoid trepanation was performed, the upper border of which was the projection of the course of the transverse sinus, the lateral border was the projection of the course of the transverse sinus, 4–4 cm in size. Further, additional dissection and dissection of the muscles above the foramen magnum were performed. The control was carried out both by palpation and by direct visualization. At this stage, it is especially important to carefully dissect the muscles in order to avoid damage to the V3 segment of the vertebral artery. After that, the posterior semicircle of the foramen magnum was resected with wire cutters up to the occipital condyle.

The dura mater (DM) was opened with its base towards the sigmoid sinus, continuing the incision to the region of the craniovertebral junction. After opening the DM, the large cerebral cistern was immediately visualized and opened, which made it possible to quickly drain the cerebrospinal fluid and relax the cerebellum. In parallel, the vertebral artery was identified for proximal control. After that, the visualization angle was changed towards the 4th ventricle and sanitation from the foramen of Magendie from blood clots was performed to obtain CSF. Further, after significant relaxation of the cerebellum, the aneurysm and the orifice of the PICA were visualized, and the caudal group of dura nerves was dissected. After preliminary dissection of the aneurysm neck, the aneurysm neck was clipped under conditions of temporary clipping on the vertebral artery. After that, the aneurysm was opened to confirm the total exclusion. Next, hemostasis was performed. The DM was closed tightly. The bone was placed in place and fixed with titanium fixators. Soft tissues were sutured in layers with a continuous intradermal suture.

After the operation, the patients were in the neurocritical care unit, after which they were transferred to the unit. Infectious complications, postoperative subcutaneous hematomas and liquorrhea were not observed. The proposed method - modified extended retrosigmoid retrocondylar access to aneurysms of the posterior inferior cerebellar artery in the acute period of hemorrhage allows for early proximal control, minimizes traction of the cerebellar hemisphere, improves visualization of the structures of the posterior cranial fossa, sanitizes the 4th ventricle from blood clots and restores CSF circulation. Ensuring the safety of surgical intervention through the use of a modified extended retrosigmoid retrocondylar approach makes it possible to ensure the effectiveness of the intervention, reduce the number of associated intra- and postoperative complications, and ensure good recovery of patients with PICA aneurysms in the acute period of hemorrhage. Below is a comparison of the lateral suboccipital approach with laminectomy of the C1 vertebra, the traditional retrosigmoid approach, and the extended retrosigmoid retrocondylar approach proposed by the authors (Fig. 1): CT with reconstruction, comparison of approaches. A - lateral suboccipital approach with laminectomy of the C1 vertebra, B - retrosigmoid approach, C - extended retrosigmoid retrocondylar approach (dotted line marks the area of resection of the foramen magnum)

Examples:

Clinical example. Patient M., 44 years old, was admitted to the neurosurgical department by SMP with complaints of a sudden headache the day before with the development of tension in the cervical-occipital region. Against the background of a headache, she noted nausea, vomiting, pain in the eyes. From the anamnesis it is known that similar headaches, but of lesser intensity, were noted a few weeks ago. Additional examination on CT of the brain revealed a massive subarachnoid hemorrhage with the presence of blood in the ventricular system, CT angiography revealed a saccular aneurysm at the mouth of the PICA on the left (Fig. 2): A - CT of a patient with massive subarachnoid hemorrhage, the arrow indicates blood in the 4th ventricle , B - PICA aneurysm on the left (arrow).

In the somatic status without features, in the neurological status, the presence of cerebral symptoms is noted. BP 125/80, heart rate 72/min. After a routine preoperative examination, the patient was taken to the operating room. During the operation, combined endotracheal anesthesia was used. Position on the operating table on the right side. The patient's head was fixed in a Mayfield brace. The site of the skin incision was infiltrated with lidocaine solution. The surgical field was treated with iodine antiseptics. A slightly arched skin incision of 9-10 cm was made in the behind-the-ear region on the right, retromastoidally within the scalp. Monopolar coagulation dissected the periosteum and sternocleidomastoid muscles. Bleeding from the emissary vein was stopped with wax. The cutter hole was placed in the region of the asterion. Then, using a craniotomy, a classic retrosigmoid trepanation was performed, the upper border of which was the projection of the course of the transverse sinus, the lateral border was the projection of the course of the transverse sinus, 4–4 cm in size. After that, the posterior semi-ring of the foramen magnum was resected with nippers on the right up to the occipital condyle.

The dura mater was opened with its base towards the sigmoid sinus, continuing the incision to the region of the craniovertebral junction. After opening the dura mater, the brain was edematous, with blood clots subpially. Next, a large cerebral cistern was visualized and opened, which made it possible to quickly drain the cerebrospinal fluid and relax the cerebellum. In parallel, the vertebral artery was identified for proximal control. In parallel, blood clots were aspirated from the 4th ventricle. Next, dissection of the caudal group of nerves was performed. After preliminary dissection of the aneurysm neck, the aneurysm neck was clipped under conditions of temporary clipping on the vertebral artery for up to 3 minutes. The aneurysm was opened to confirm the total exclusion. Hemostasis. The DM was closed tightly. The bone was placed in place and fixed with titanium fixators. Soft tissues were sutured in layers with a continuous intradermal suture. An aseptic bandage was applied.

The postoperative period was uneventful, without complications. After the operation, the patient was in the intensive care unit for a neurological profile for a day, and the next day she was transferred to the department. Complications were not observed. Therapy was carried out for the transferred subarachnoid hemorrhage, the cerebrospinal fluid was sanitized using repeated lumbar punctures. She was discharged without complications on the 7th day after the operation.

Intraoperative photographs and postoperative CT follow-up are shown in Fig. 3: Intraoperative photographs. A - an extended retrosigmoid approach was performed with resection of the BZO semicircle (arrow), B - the DM is opened above the craniovertebral junction (arrow), subpial hemorrhages are observed in the cerebellar hemisphere, C - access is made to the large cerebral cistern, which is visualized immediately after opening the DM (arrow) ), D - sanitation of the large cerebral cistern from blood was carried out, clots were removed from the 4th ventricle, the arrow shows the medulla oblongata, D - the aneurysmal sac is shown by the arrow, E - clipping of the aneurysm was performed; and in FIG. 4: Postoperative CT data. A - the area of resection of the BSO on the left is visualized, B - the aneurysm is clipped, a clip is visualized on the neck of the aneurysm.

Claims (1)

A method for retrosigmoid retrocondylar access to aneurysms of the posterior inferior cerebellar artery in the acute period of hemorrhage, characterized in that when performing said access, the posterior half-ring of the foramen magnum is additionally resected to the occipital condyle.

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