Santiago Hem

A New Classification of Complications in Neurosurgery

OBJECTIVE To define and grade neurosurgical and spinal postoperative complications based on their need for treatment. METHODS Complications were defined as any deviation from the normal postoperative course occurring within 30 days of surgery. A four-grade scale was proposed based on the therapy used to treat the complications: grade I, any non-life-threatening complications treated without invasive procedures; grade II, complications requiring invasive management such as surgical, endoscopic, and endovascular procedures; grade III, life-threatening adverse events requiring treatment in an intensive care unit (ICU); and grade IV, deaths as a result of complications. Each grade was classified as a surgical or medical complication. An observational test of this system was conducted between January 2008 and December 2009 in a cohort of 1190 patients at the Hospital Italiano de Buenos Aires. RESULTS Of 167 complications, 129 (10.84%) were classified as surgical, and 38 (3.19%) were classified as medical complications. Grade I (mild) complications accounted for 31.73%, grade II (moderate) complications accounted for 25.74%, and grade III (severe) complications accounted for 34.13%. The overall mortality rate was 1.17%; 0.84% of deaths were directly related to surgical procedures. CONCLUSIONS The authors present a simple, practical, and easy to reproduce way to report negative outcomes based on the therapy administered to treat a complication. The main advantages of this classification are the ability to compare surgical results among different centers and times, the ability to compare medical and surgical complications, and the ability to perform future meta-analyses.

Sternberg's canal as a cause of encephalocele within the lateral recess of the sphenoid sinus: A report of two cases

Background: Intrasphenoidal encephaloceles are extremely rare findings. Sternbergs canal is a lateral craniopharyngeal canal resulting from incomplete fusion of the greater wings of the sphenoid bone with the basisphenoid. It acts as a weak spot of the skull base, which may lead to develop a temporal lobe encephalocele protruding into the lateral recess of the sphenoid sinus (SS). Case Description: We present two cases of intrasphenoidal encephalocele due to persistence of the lateral craniopharyngeal canal. The first case presented with cerebrospinal fluid (CSF) rhinorrhea and the second one was referred to the neurosurgical department with CSF rhinorrhea and meningitis. Radiological investigations consisted of computed tomography (CT) scan, CT cisternography and magnetic resonance images in both cases. These imaging studies identified a herniated temporal lobe through a bony defect which communicates the middle cranial fossa with the lateral recess of the SS. Both patients underwent a transcranial repair of the encephalocele because of the previous failure of the endoscopic surgery. There was no complication related to the surgical procedure and no recurrence of CSF leakage occurred 2 and 3 years after surgery, respectively. Conclusion: Encephalocele within the lateral recess of the SS is a rare entity which must be suspected in patients who present with spontaneous CSF rhinorrhea. Congenital intrasphenoidal encephaloceles, which are located medial to the foramen rotundum, seem to be due to persistence of the Sternbergs canal. Transcranial approach is a good option when a transnasal approach had failed previously.

Dorsal column stimulator applications

Background: Spinal cord stimulation (SCS) has been used to treat neuropathic pain since 1967. Following that, technological progress, among other advances, helped SCS become an effective tool to reduce pain. Methods: This article is a non-systematic review of the mechanism of action, indications, results, programming parameters, complications, and cost-effectiveness of SCS. Results: In spite of the existence of several studies that try to prove the mechanism of action of SCS, it still remains unknown. The mechanism of action of SCS would be based on the antidromic activation of the dorsal column fibers, which activate the inhibitory interneurons within the dorsal horn. At present, the indications of SCS are being revised constantly, while new applications are being proposed and researched worldwide. Failed back surgery syndrome (FBSS) is the most common indication for SCS, whereas, the complex regional pain syndrome (CRPS) is the second one. Also, this technique is useful in patients with refractory angina and critical limb ischemia, in whom surgical or endovascular treatment cannot be performed. Further indications may be phantom limb pain, chronic intractable pain located in the head, face, neck, or upper extremities, spinal lumbar stenosis in patients who are not surgical candidates, and others. Conclusion: Spinal cord stimulation is a useful tool for neuromodulation, if an accurate patient selection is carried out prior, which should include a trial period. Undoubtedly, this proper selection and a better knowledge of its underlying mechanisms of action, will allow this cutting edge technique to be more acceptable among pain physicians.

Polyetheretherketone interbody cages versus autogenous iliac crest bone grafts with anterior fixation for cervical disc disease.

Objective: The aim of this study was to compare the fusion rate, operation time, recovery of disc space height, clinical duration and improvement, return to activities of daily living, and complication rate associated with anterior cervical discectomy with interbody fusion by using polyetheretherketone cages or autogenous iliac crest bone grafts as disc replacement in a series of 60 patients. Materials and Methods: Between November 2006 and February 2010 a retrospective analytical observational cohort study was carried out in 60 consecutive patients surgically treated with anterior cervical discectomy with interbody fusion for degenerative disc desease at the Neurosurgical Department of the Hospital Italiano de Buenos Aires. The patients were divided into 2 groups for the assessment of clinical characteristics, demographics, fusion rates, duration of surgical procedure, neurological and functional outcomes, imaging results, and complications. Group A included patients treated with autogenous iliac crest bone grafts, and group B included patients treated with polyetheretherketone cages. Results: The mean age of the patients was 50.8 years. Female patients comprised the majority in both groups (63.3%). Cervicobrachialgia was the most common presentation. Clinical improvement, fusion rates, and recovery of disc space height were similar in both groups. The operation time was significantly shorter in the polyetheretherketone group (P<0.001). Twenty percent (n=6) of the patients in group A suffered complications, >80% of which were associated with iliac crest bone graft harvesting. Patients in group B had no complications (P<0.05). Conclusions: Although outcomes were very successful in both groups in terms of fixation stability, recovery of disc space, return to activities of daily living and work, and remission of symptoms, operation time was considerably shorter for patients in the polyetheretherketone group, who had none of the complications associated with iliac crest bone graft harvesting, both differences being statistically significant.

Identifying the trigeminal nerve branches for transovale radiofrequency thermolesion: "no pain, no stress".

BACKGROUND: Radiofrequency thermorhizotomy of the trigeminal nerve is a known treatment of trigeminal neuralgia. Analysis of verbal responses to electric stimulation of the trigeminal rootlets has been the only method available to localize the affected branch, but patient discomfort may lead to unreliable verbal responses, resulting in increased morbidity or even therapeutic failure. Orthodromically elicited evoked potentials of the trigeminal nerve have also been used, but their application is tedious and results may vary. OBJECTIVE: To develop an electrophysiological method for intraoperative localization of the trigeminal nerve branches. METHODS: A series of 55 patients under general anesthesia during radiofrequency thermorhizotomy were studied. The trigeminal nerve root was stimulated through the foramen ovale with the RF electrode. Antidromic responses were recorded from the 3 divisions of the trigeminal nerve in the face. Effectiveness rate, pain relief, recurrence, complications, and patient comfort after the procedure were analyzed. RESULTS: Reproducible and easily obtained antidromic responses were clearly recorded in every subdivision of the trigeminal nerve in all patients. Ninety-four percent of patients experienced immediate pain relief after the procedure. The recurrence rate was 12.72%, and the surgical morbidity was 20%. CONCLUSION: This method proved to be useful to determine the exact localization of individual subdivisions of the trigeminal nerve in anesthetized patients, making this procedure safer and more comfortable for them. ABBREVIATION: RF-TL, radiofrequency thermolesioning

Unsuccessful pulsed radiofrequency of the sphenopalatine ganglion in patients with chronic cluster headache and subsequent successful thermocoagulation.

We present the results of pulsed and continuous radiofrequency (CRF) of the sphenopalatine ganglion in a case series of 3 patients with chronic cluster headache (CCH). Three patients were referred to our neurosurgical department because of CCH, which was refractory to pharmacological treatment. They underwent pulsed radiofrequency of the sphenopalatine ganglion (PRF‐SPG), and the procedure was performed through an infrazygomatic approach. In the PRF procedures, we applied 2 cycles of PRF at 42°C and 45 V for 120 seconds, with a pulse frequency of 2 Hz and a pulse width of 20 ms. In those procedures where thermocoagulation was carried out, 2 CRF lesions at 80°C for 90 seconds each were performed. Following corticosteroid and local anesthetic (40 mg of methylprednisolone and 1 mL of 1% lidocaine) injection, 2 patients had no pain relief at all, whereas the third one experienced a partial response, which lasted only 1 month and his pain then returned to its baseline level. Thus, this outcome was assessed as a nonsustained partial response. Therefore, all of them underwent a CRF lesioning of the SPG, and after this procedure, they achieved complete pain relief until the end of the follow‐up period. Furthermore, the associated autonomic manifestations disappeared. The 3 patients presented in this case series failed to achieve adequate pain relief after PRF‐SPG. However, these same patients subsequently underwent a successful CRF of the SPG.

A new model for dura mater healing: human dural fibroblast culture

Abstract Objective: Dura mater healing is crucial to prevent cerebrospinal fluid (CSF) leaks after neurosurgical procedures. Biological mechanisms leading to dural closure are only partially understood and have been studied in animals exclusively. We studied an in vitro model of dural closure which uses human cells. Materials and methods: We used human dura intended for disposal after surgery. Explant primary cultures were performed. Cells were characterized through common staining and immunohistochemistry. A cell growth curve was elaborated and the effect of dexamethasone on cell count was assessed. Spongostan®, oxidized regenerated cellulose and autologous plastic materials were also evaluated for their effect on cellular growth. Results: All specimens showed growth in fusiform cells, which project pseudopods and fuse into spindles. Cells showed desmin and vimentin positivity, and were negative for all the other stains, behaving phenotypically like fibroblasts. No collagen base was necessary for cell growth. Dexamethasone decreased cell count in the primary culture as well as in the explant, and reduced the cell proliferation marker Ki-67. Spongostan® was successfully used as a graft, and fibroblast cultures were additionally developed with muscle, pericranium, galea, and fascia. Oxidized cellulose induced cell death by lowering the pH of the solution. Discussion: According to the findings, unlike mini-pigs and rabbits, in humans, dural fibroblast sensitivity to collagen seems to be lower. Dexamethasone inhibits fibroblast invasion, which is the biological base of wound dehiscence in cranial surgery. Although Spongostan is useful, Surgicel® can lower the media pH, thereby inhibiting cellular growth.

Ectopic prolactinoma within the sphenoidal sinus associated with empty sella

Background: Pituitary adenomas are a common cause of endocrinal dysfunction, which comprise 10–20% of all intracranial tumors. Although almost all of them arise within the sella turcica, there are some rare cases in which a pituitary adenoma is located outside the intrasellar region, so it is defined as an ectopic pituitary adenoma (EPA). Case Description: We described a case of a 31-year-old male with a serum prolactin (PRL) value of 240 ng/ml Magnetic resonance imaging (MRI) showed a space-occupying mass within the sphenoid sinus (SS) which partially enhanced by gadolinium. MRI did not reveal any sellar floor defect and an empty sella was detected. As dopamine agonist treatment had failed in lowering the serum PRL level, he underwent surgical treatment. A transsphenoidal approach without opening the sellar floor was performed using an operating microscope and the lesion within the SS was completely removed. Conclusion: Although intrasphenoidal EPAs are rare findings, the presence of an endocrine disorder related to pituitary hormones, and a space-occupying mass within the SS associated with either a normal sellar pituitary gland or an empty sella must lead us to suspect this diagnosis.

Pathological changes of the hippocampus and cognitive dysfunction following frontal lobe surgery in a rat model.

BackgroundPostoperative cognitive dysfunction (POCD) is a known complication after intracranial surgery. Impaired hippocampal neurogenesis has been associated with cognitive dysfunction in animal models.MethodsIn order to assess hippocampal changes after brain surgery, a frontal lobe corticectomy was performed in ten adult Wistar rats (group 4). Three different control groups (n = 10 each) included no treatment (G1), general anesthesia alone (G2), and craniectomy without dural opening (G3). Twenty-four hours after surgery, half of the animals were killed, and the mRNA levels for IL-6, TNF-α, and brain-derived growth factor (BDNF) in the contralateral hippocampus were assessed by qPCR. Seven days later, the remaining animals underwent anxiety and memory testing. Afterwards, the number of immature neurons in the hippocampal cortex was measured by doublecortin (DCX) staining.ResultsTwenty-four hours after surgery, mRNA levels of IL-6 and TNF-α increased and BDNF decreased in both surgical groups G3 and G4 (p = 0.012). Cognitive tests demonstrated an increase in anxiety levels and memory impairment in surgical groups compared with non-surgical animals. These changes correlated with an inhibition of hippocampal neurogenesis evidenced by a decreased number of new neurons (mean ± SD for G1-4: 66.4 ± 24; 57.6 ± 22.2; 21.3 ± 3.78; 5.7 ± 1.05, p < 0.001, non-parametric ANOVA).ConclusionsIntracranial surgery was demonstrated to induce an inflammatory reaction within the hippocampus that compromised neurogenesis and impaired normal cognitive processing. Corticectomy had a greater effect than craniotomy alone, indicating a central trigger for hippocampal inflammatory changes. POCD after craniotomy may originate from a central inflammatory response resulting from surgical trauma to the brain parenchyma.

Cirugía transnasal endoscópica para tumores de hipófisis

Introducción: Exponer la técnica utilizada y los resultados obtenidos en los primeros 52 pacientes portadores de tumores hipofisarios tratados por la vía endoscópica transnasal en el Hospital Italiano de Buenos Aires Métodos: Se llevó a cabo un análisis retrospectivo de 52 cirugías endoscópicas transnasales utilizadas en el tratamiento de tumores hipofisários. Las mismas fueron realizadas en el Hospital Italiano de Buenos Aires durante el período junio del 2011 a junio del 2012. Se analizaron las características demográficas de los pacientes, la patología de base y la morbimortalidad asociada a la cirugía. Resultados: La edad media de los pacientes fue de 41,52 años con un rango de 18-79. La distribución fue similar entre hombres y mujeres. Las patologías más frecuentes fueron: adenomas no funcionantes (40.4%), tumores productores de GH/Acromegalia (25%) y tumores productores de ACTH/Enfermedad de Cushing (23.1%). Aproximadamente el 70 % correspondieron a macroadenomas. Sólo un paciente presentó complicaciones. No se registro ningún óbito. Conclusión: Si bien podremos objetivar fehacientemente resultados más concluyentes en futuros trabajos, podemos decir a priori que, en la endoscopía el detalle anatómico es claramente superior al microscópico y que la posibilidad de la introducción del endoscopio en la silla turca permite la visualización directa de remanentes tumorales, de sitios de fístula y como así también de la glándula normal, ventajas que potencialmente podrían permitir obtener mejores resultados quirúrgicos, en términos de control de la enfermedad y tasa de complicaciones.