Operating room preparation for COVID-19

Operating room preparation for COVID-19

Ti et al. published what they do preparing an operating room (OR) when a confirmed or suspected COVID-19 patient needs an operation 1).

An operating room with a negative room pressure environment located at a corner of the operating complex, and with separate access, is designated for all confirmed (or suspected) COVID-19 cases. The OR actually consists of five interconnected rooms, of which only the anteroom and anesthesia induction rooms have negative atmospheric pressures. The OR proper, preparation and scrub rooms all have positive pressures.

Understanding the airflow within the OR is crucial to minimizing the risk of infection.

The same OR and the same anesthesia machine will only be used for COVID-19 cases for the duration of the epidemic. An additional heat and moisture exchanger (HME) filter is placed on the expiratory limb of the circuit. Both HME filters and the soda lime are changed after each case. The anesthetic drug trolley is kept in the induction room. Before the start of each operation, the anesthesiologist puts all the drugs and equipment required for the procedure onto a tray to avoid handling of the drug trolley during the case. Nevertheless, if there is a need for additional drugs, hand hygiene and glove changing are performed before entering the induction room and handling the drug trolley.

A fully stocked airway trolley is also placed in the induction room. As far as possible, disposable airway equipment is used. The airway should be secured using the method with the highest chance of first-time success to avoid repeated instrumentation of the airway, including using a video-laryngoscope.

Equipment in limited supply such as bispectral index monitors or infusion pumps may be requested but need to be thoroughly wiped down after use.

Hospital security is responsible for clearing the route from the ward or intensive care unit (ICU) to the OR, including the elevators. The transfer from the ward to the OR will be done by the ward nurses in full personal protective equipment (PPE) including a well-fitting N95 maskgoggles or face shieldsplash-resistant gown, and boot covers. For patients coming from the ICU, a dedicated transport ventilator is used. To avoid aerosolization, the gas flow is turned off and the endotracheal tube clamped with forceps during the switching of ventilators. The ICU personnel wear full PPE with a powered air-purifying respirator (PAPR) for the transfer. In the induction room, a PAPR is worn during induction and reversal of anesthesia for all personnel within 2 m of the patient. For operative airway procedures such as tracheostomy, all staff keep their PAPR on throughout the procedure.

During the procedure, a runner is stationed outside the OR if additional drugs or equipment are needed. These are placed onto a trolley that will be left in the ante room for the OR team to retrieve. This same process in reverse is used to send out specimens such as arterial blood gas samples and frozen section specimens. The runner wears PPE when entering the ante room.

Personnel exiting the OR discard their used gowns and gloves in the ante room and perform hand hygiene before leaving the ante room. Any PAPR will be removed outside the ante room. Patients who do not require ICU care postoperatively are fully recovered in the OR itself. When the patient is ready for discharge, the route to the isolation ward or ICU is again cleared by security.

A minimum of one hour is planned between cases to allow OR staff to send the patient back to the ward, conduct through decontamination of all surfaces, screens, keyboard, cables, monitors, and anesthesia machine. All unused items on the drug tray and airway trolley should be assumed to be contaminated and discarded. All staff have to shower before resuming their regular duties. As an added precaution, after confirmed COVID-19 cases, a hydrogen peroxide vaporizer will be used to decontaminate the OR.

1)

Ti LK, Ang LS, Foong TW, Ng BSW. What we do when a COVID-19 patient needs an operation: operating room preparation and guidance. Can J Anaesth. 2020 Mar 6. doi: 10.1007/s12630-020-01617-4. [Epub ahead of print] PubMed PMID: 32144591.

Cerebellar hemangioblastoma surgery

Cerebellar hemangioblastoma surgery

Preoperative embolization of cerebellar hemangioblastoma may help reduce the vascularity.

Solid HGBs tend to be more difficult to remove. They are treated like AVMs (avoid piecemeal removal), working along margin and devascularizing blood supply. A helpful technique is to shrink the tumor by laying a length of bipolar forceps along tumor surface and coagulating. HGBs with attachment to floor of 4th ventricle may be hazardous to remove (cardio-respiratory complications).

Multiple lesions: if ≥ 0.8–1 cm diameter: may treat as in solitary lesion. Smaller and deeper lesions may be difficult to locate at the time of surgery.

Surgical treatment of cerebellar hemangioblastoma is total resection, with the main goal being the preservation of surrounding neural tissue.

The tumors usually are well demarcated from the surrounding brain or spinal cord, but this border of separation does not contain any particular membrane or capsule.

Multiple feeding arteries are often present, as well as more than one abnormally thick draining vein, with large diameters and thick walls.

Simultaneous 3D visualization of feeding arteries, draining veins, and surrounding structures is needed.

The surgical approach must be wide enough to avoid compression of the healthy tissues during retraction. Thorough evaluation of preoperative imaging studies is the key to the safest possible exposure of the tumor.

A study evaluated the usefulness of high-resolution 3D multifusion medical imaging (hr-3DMMI) for preoperative planning of hemangioblastoma. The hr-3DMMI combined MRI, MR angiography, thin-slice CT, and 3D rotated angiography. Surface rendering was mainly used for the creation of hr-3DMMI using multiple thresholds to create 3D models, and processing took approximately 3-5 hours. This hr-3DMMI technique was used in 5 patients for preoperative planning and the imaging findings were compared with the operative findings. Hr-3DMMI could simulate the whole 3D tumor as a unique sphere and show the precise penetration points of both feeding arteries and draining veins with the same spatial relationships as the original tumor. All feeding arteries and draining veins were found intraoperatively at the same position as estimated preoperatively, and were occluded as planned preoperatively. This hr-3DMMI technique could demonstrate the precise locations of feeding arteries and draining veins preoperatively and estimate the appropriate route for resection of the tumor. Hr-3DMMI is expected to be a very useful support tool for surgery of hemangioblastoma 1).


Occasionally, a localized flow and rich blood supply within the tumor is observed and the color of intravenous blood is bright red 2).

The surface of the tumor may be coagulated with wide bipolar forceps; however, avoid penetration of the tumor itself because of its extreme vascularity and difficulties with hemostasis. Try to dissect the tumor circumferentially by careful coagulation and cutting the small feeding vessels and adhesions between the tumor and the surrounding parenchyma and by putting cottonoid strips into the developing plane to avoid direct pressure.

Once the feeding vessels are identified, they are coagulated and cut. Try to coagulate the arterial feeders prior to the draining veins, but this is not as crucial as it is in arteriovenous malformations. After the tumor is totally removed, the raw surface of the cerebellum remains relatively bloodless, and the oozing blood stops after a few minutes of gently packing the resection cavity with wet cotton balls, avoiding the need for additional coagulation.

Cerebrospinal fluid diversion is rarely necessary after complete tumor removal in patients with preoperative hydrocephalus.

Tumor recurrence is avoided by meticulous extracapsular resection 3).

If an associated hydrocephalus exists, it must be addressed separately, usually by means of external ventricular drainage (EVD) prior to tumor resection. After the tumor is removed, the need for permanent shunt placement may be determined by the patient’s response to EVD clamping.

Cystic cerebellar hemangioblastoma surgery

The tumor is usually easy to visualize because of its reddish-colored solid component and the yellow fluid inside the cyst.

Cystic HGBs require removal of the mural nodule (otherwise, the cyst will recur). The cyst wall is not removed unless there is evidence of tumor within the cyst wall on MRI (typically thick-walled cysts) or visually at the time of surgery.

5-ALA fluorescence may aid in the visual localization of small hemangioblastomas within the cyst wall.

Cystic brainstem HGB: the solid nodule of the tumor is removed under the microscope by bipolar- ing and cutting the gliotic adhesions to the parenchyma. Removal of the cyst wall is not necessary. There is often a cleavage between the tumor and the floor of the fourth ventricle which facilitates tumor removal. To reduce bleeding, avoid piecemeal removal. Preserve large draining veins until the arterial feeders to the mural nodule have been isolated and resected.


Surgical resection is the most effective treatment for cerebellar hemangioblastomas with an enhanced cystic wall 4). However, for this type of lesion, the tumor must not be punctured, biopsied or blocked via resection due to the rich blood supply. The enhanced tumor wall indicates that it contains partial tumor cells, therefore to avoid recurrence of the tumor, the wall and the solid part of the tumor require total resection 5).

If the cyst is present, it may be emptied by cutting the covering pial membrane or by aspirating the cystic contents using a syringe with a short small-caliber needle. Decompression of the cyst allows for improved delineation of the interface between the tumor.

Videos



Case reports

2 patients with von Hippel-Lindau disease-related hemangioblastomas successfully treated by a fully endoscopic transcranial approach via a short skin incision and a 2 cm × 2 cm small bony window. Before surgery, a three-dimensional virtual reality model was created to determine the ideal trajectory.

Patient 1 had 2 serial large cystic tumors that equally contributed to obstructive hydrocephalus and were resected sequentially via a single endoscopic trajectory. Patient 2 had a progressive large cystic tumor that was resected endoscopically. Complete resection of the tumors was achieved without any complications in either patient.

Small nodular tumors accompanying a large cyst are plausible candidates for endoscopic transcranial surgery. The spatial relationship of nodules, cyst, and cerebellar parenchyma is important to determine the applicability of the present technique. Preoperative three-dimensional virtual reality simulation helps assess the feasibility of this approach 6).


Krüger et al. presented the case of a minimally invasive removal of a superficial cerebellar hemangioblastoma with tumor-associated cyst and indicate the potential benefits and limitations of this technique 7).

References

1)

Yoshino M, Nakatomi H, Kin T, Saito T, Shono N, Nomura S, Nakagawa D, Takayanagi S, Imai H, Oyama H, Saito N. Usefulness of high-resolution 3D multifusion medical imaging for preoperative planning in patients with posterior fossa hemangioblastoma: technical note. J Neurosurg. 2016 Aug 26:1-9. [Epub ahead of print] PubMed PMID: 27564468.
2) , 5)

Jito J, Nozaki K. Treatment strategies for cerebellar hemangioblastomas: simple or further studies? World Neurosurg. 2014 Nov;82(5):619-20. doi: 10.1016/j.wneu.2014.08.018. Epub 2014 Aug 20. PubMed PMID: 25151228.
3)

Jagannathan J, Lonser RR, Smith R, DeVroom HL, Oldfield EH. Surgical management of cerebellar hemangioblastomas in patients with von Hippel-Lindau disease. J Neurosurg. 2008 Feb;108(2):210-22. doi: 10.3171/JNS/2008/108/2/0210. PubMed PMID: 18240914.
4)

Neumann HP, Eggert HR, Weigel K, Friedburg H, Wiestler OD, Schollmeyer P. Hemangioblastomas of the central nervous system. A 10-year study with special reference to von Hippel-Lindau syndrome. J Neurosurg. 1989 Jan;70(1):24-30. PubMed PMID: 2909683.
6)

Hasegawa H, Shin M, Kin T, Saito N. Fully Endoscopic Minimally Invasive Tumor Resection for Cystic Cerebellar Hemangioblastoma. World Neurosurg. 2019 Jun;126:484-490. doi: 10.1016/j.wneu.2019.03.158. Epub 2019 Mar 26. PubMed PMID: 30922906.
7)

Krüger MT, Klingler JH. Resection of a cerebellar hemangioblastoma via a minimally invasive tubular approach. J Clin Neurosci. 2019 May;63:240-243. doi: 10.1016/j.jocn.2019.01.045. Epub 2019 Feb 4. PubMed PMID: 30732985.

Trigonocephaly

Trigonocephaly

In this pathology different degrees of dysmorphia of the anterior cranial fossa and the presence of associated anomalies of the skull might enable specific subgroups to be identified.

Neurosurgeons, maxillofacial and plastic surgeons will be increasingly concerned with trigonocephaly because of the increase in prevalence observed over the last two decades. Cytogenetic alterations are probably underestimated in this craniosynostosis, considering the high rate of neurodevelopmental retardation compared to other single-suture synostoses. Genetic counseling is, therefore, more and more effective in this pathology. An objective method to evaluate the cosmetic results of both endoscopic and open surgeries is necessary, as some under-corrections have been reported with minimally invasive surgery 1).

Epidemiology

The cause of trigonocephaly is attributed to premature closure of the metopic suture.

Trigonocephaly is a relatively uncommon form of craniosynostosis, with an incidence of 0.3 per 1000 live births.

The prevalence of trigonocephaly increased during the last two decades both in Europe and in the United States, but no clear contributing factors have yet been identified 2).

Etiology

Chromosomal abnormalities described in metopic synostosis comprised deletion of chromosome 11q24, deletion or trisomy of 9p and deletion of 7p, deletions of 3q, 13q, 12pter, 22q11, and duplication of 15q25. SMAD6 mutations should be systematically screened for in familial cases. 3).

Diagnosis

Trigonocephaly diagnosis.

Review

The aim of a review of Mocquard et al. was to report on recent advances in trigonocephaly since the last report on craniosynostosis published in 2006.

The review was conducted in accordance with the PRISMA guidelines. Research focused on four main topics: epidemiology, neurodevelopmental disorders, genetics and surgical techniques.

Forty reports were included. The prevalence of trigonocephaly increased during the last two decades both in Europe and in the United States, but no clear contributing factors have yet been identified. Neurodevelopmental disorders are frequent in syndromic trigonocephaly and not particularly rare in non-syndromic cases (up to 34%). Developmental retardation (speech, motor or global) was almost always present in children exposed to valproic acid. Chromosomal abnormalities described in metopic synostosis comprised deletion of chromosome 11q24, deletion or trisomy of 9p and deletion of 7p, deletions of 3q, 13q, 12pter, 22q11, and duplication of 15q25. SMAD6 mutations should be systematically screened for in familial cases. Recent advances in surgical techniques have mainly concerned endoscopic-assisted procedures, as they significantly reduce perioperative morbidity.

Neurosurgeons, maxillofacial and plastic surgeons will be increasingly concerned with trigonocephaly because of the increase in prevalence observed over the last two decades. Cytogenetic alterations are probably underestimated in this craniosynostosis, considering the high rate of neurodevelopmental retardation compared to other single-suture synostoses. Genetic counselling is therefore more and more effective in this pathology. An objective method to evaluate the cosmetic results of both endoscopic and open surgeries is necessary, as some under-corrections have been reported with minimally invasive surgery 4).

Treatment

Trigonocephaly treatment.

Case series

Trigonocephaly case series.

Case reports

A patient with microcephaly and trigonocephaly, moderate intellectual disability, speech and language delay, and poor social interaction in addition to minor but atypical dysmorphic features. This report provides further insight into the pathogenicity of the Xp22.31 duplication by extending knowledge of its clinical features. This case, in association with those reported in the literature, indicates that the Xp22.31 duplication may contribute to cause pathological phenotypes with minor facial dysmorphisms, microcephaly, and intellectual disability as main features 5).


The diagnosis of a combination of both Sturge-Weber syndrome and trigonocephaly has been reported. Ristow et al., presents a patient with the unusual findings of a Sturge-Weber syndrome and simultaneous trigonocephaly induced by premature metopic synostosis. Thus, the rare combination of a port-wine stain involving the first division of the trigeminal nerve with the diagnosis of a craniosynostosis justifies the indication of a prophylactic magnetic resonance imaging acquisition before craniofacial surgeries, in order to prevent seizures and stroke-like episodes triggered by the surgical intervention 6).

References

1) , 2) , 3) , 4)

Mocquard C, Aillet S, Riffaud L. Recent advances in trigonocephaly. Neurochirurgie. 2019 Nov;65(5):246-251. doi: 10.1016/j.neuchi.2019.09.014. Epub 2019 Sep 27. Review. PubMed PMID: 31568780.
5)

Pavone P, Corsello G, Marino S, Ruggieri M, Falsaperla R. Microcephaly/Trigonocephaly, Intellectual Disability, Autism Spectrum Disorder, and Atypical Dysmorphic Features in a Boy with Xp22.31 Duplication. Mol Syndromol. 2019 Jan;9(5):253-258. doi: 10.1159/000493174. Epub 2018 Oct 2. PubMed PMID: 30733660; PubMed Central PMCID: PMC6362926.
6)

Ristow O, Freudlsperger C, Berger M, Bächli H, Hoffmann J, Engel M. Combination of Sturge-Weber Syndrome and Trigonocephaly. J Craniofac Surg. 2016 Aug 24. [Epub ahead of print] PubMed PMID: 27557468.

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