Successful retrograde regeneration using a sensory branch for motor nerve transfer.

OBJECTIVE: The objective of this study was to test whether regenerating motor axons from a donor nerve can travel in a retrograde fashion using sensory branches to successfully reinnervate a motor nerve end organ. METHODS: This study has two parts. In part I, rats (n = 30) were assigned to one of five groups for obturator nerve (ON)-to-femoral nerve transfer: group 1, ON-to-saphenous nerve (SN) distal stump; group 2, ON-to-SN proximal stump without femoral nerve proper (FNP) injury; group 3, ON-to-SN proximal stump with FNP crush injury; group 4, ON-to-SN proximal stump with FNP transection injury; and group 5, gold standard transfer, ON-to-motor femoral nerve (MFN) branch. At 8 weeks, retrograde labeling was done from the distal MFN, and the spinal cords were examined to assess the degree of obturator motor axon regeneration across the five groups. In part II, only group 4 was examined (n = 8). Through use of immunostaining and optical tissue clearing methods, the nerve transfer networks were cleared and imaged using light-sheet fluorescence microscopy to visualize the regeneration pathways in 2D and 3D models at 2- and 8-week time points. RESULTS: Proximal FNP transection (group 4) enabled a significantly higher number of retrogradely regenerated motor axons compared with control groups 1-3. Moreover, group 4 had modest, but nonsignificant, superiority of motor neuron counts compared with the positive control group, group 5. Optical tissue clearing demonstrated that the axons traveled in a retrograde fashion from the recipient sensory branch to the FNP mixed stump, then through complex turns, down to distal branches. Immunostaining confirmed the tissue clearing findings and suggested perineurium disruption as a means by which axons could traverse across fascicular boundaries. CONCLUSIONS: Sensory branches can transmit regenerating axons from donor nerves back to main mixed recipient nerves, then distally toward target organs. The extent of retrograde regeneration is markedly influenced by the type and severity of injury sustained by the recipient nerve. Using a sensory branch as a bridge for retrogradely regenerating axons can open new potential horizons in nerve repair surgery for severely injured mixed nerves.

Removal of Capybara (Hydrochoerus hydrochaeris) population as measure to control Amblyomma tick population and reduce Brazilian Spotted Fever transmission risk in a Gated Community in Bragança Paulista (SP, Brazil) ­ Case Study / Remoção de capivaras (Hydrochoerus hydrochaeris) como ação para controle da população de carrapatos Amblyomma e redução do risco de transmissão da Febre Maculosa Brasileira em um Condomínio Residencial em Bragança Paulista (SP, Brasil) ­ Estudo de Caso

This study reports the factors which led a gated community located in Bragança Paulista (SP, Brazil), a non-endemic area for Brazilian Spotted Fever (BSF), to be classified as a Risk Area for transmission of this disease, showing that an increasing resident population of capybaras (Hydrochoerus hydrochaeris) in the area was likely responsible for a proliferation of Amblyomma sculptum ticks and acted as an amplifying host for Rickettsia rickettsii, the main etiologic agent of BSF. We report management actions proposed to control the local tick burden and reduce BSF risk, including measures to control parasitic and free-living tick populations and exclusion of the resident capybara population. Analyses of tick population data and R. rickettsii serology tests indicate that these measures were effective, greatly reducing the environmental burden of Amblyomma sculptum ticks and reducing the BSF transmission risk at the area.(AU)

Este estudo relata os fatores que levaram um Residencial localizado em Bragança Paulista (SP, Brasil), área não-endêmica para Febre Maculosa Brasileira (FMB), a ser classificado como Área de Risco para a doença, mostrando que uma crescente população residente de capivaras (Hydrochoerus hydrochaeris) na área era a provável responsável por uma proliferação de carrapatos Amblyomma sculptum e estava atuando como hospedeiro amplificador da bactéria Rickettsia rickettsii, principal agente etiológico da FMB. Relatamos as ações de manejo ambiental propostas para controlar a quantidade de carrapatos no local e reduzir o risco de transmissão da doença, incluindo medidas para o controle de populações de carrapatos parasíticas e no ambiente e a eliminação da população residente de capivaras. Análises de dados populacionais de carrapatos e testes serológicos para R. rickettsii indicaram que as medidas tomadas foram efetivas, causando grande redução da população de carrapatos no ambiente e reduzindo o risco de transmissão de FMB na área.(AU)

Basilar Artery Ectasia Causing Trigeminal Neuralgia: An Evolved Technique of Transpositional Suture-Pexy.

BACKGROUND: Microvascular decompression for patients with trigeminal neuralgia (TGN) is widely accepted as one of the modalities of treatment. The standard approach has been retrosigmoid suboccipital craniotomy with placement of a Teflon pledget to cushion the trigeminal nerve from the offending artery, or cauterize and divide the offending vein(s). However, in cases of severe compression caused by a large artery, the standard decompression technique may not be effective. OBJECTIVE: To describe a unique technique of vasculopexy of the ectatic basilar artery to the tentorium in a patient with TGN attributed to a severely ectatic and tortuous basilar artery. A case series of patients who underwent this technique of vasculopexy for arterial compression is presented. METHODS: The patient underwent a subtemporal transtentorial approach and the basilar artery was mobilized away from the trigeminal nerve. A suture was then passed through the wall of the basilar artery (tunica media) and secured to the tentorial edge, to keep the artery away from the nerve. RESULTS: The neuralgia was promptly relieved after the operation, with no complications. A postoperative magnetic resonance imaging scan showed the basilar artery to be away from the trigeminal root. In a series of 7 patients who underwent this technique of vasculopexy, no arterial complications were noted at short- or long-term follow-up. CONCLUSION: Repositioning and vasculopexy of an ectatic basilar artery for the treatment of TGN is safe and effective. This technique can also be used for other neuropathies that result from direct arterial compression.

Brain Stem Cavernous Malformations: Operative Nuances of a Less-Invasive Resection Technique.

BACKGROUND: Different operative techniques are reported for the resection of brainstem cavernous malformations (BSCMs). The senior author has previously reported on a less-invasive technique of entering the brain stem with piecemeal removal of BSCMs, especially the deep-seated ones. OBJECTIVE: To present a larger series of these lesions, emphasizing the approach to the brain stem via case selection. We discuss the nuances of the less-invasive operative technique through case illustrations and intraoperative videos. METHODS: A retrospective review of 46 consecutive cases of BSCMs, with their clinical and radiographic data, was performed. Nine cases were selected to illustrate 7 different operative approaches, and discuss surgical nuances of the less-invasive technique unique to each. RESULTS: Postoperative morbidity, defined as an increase in modified Rankin Scale, was observed in 5 patients (10.9%). A residual BSCM was present in 2 patients (4.3%); both underwent reoperation to remove the remainder. At follow-up of 31.1 ± 27.8 mo, 3 patients experienced recurrence (6.5%). Overall, 65% of our patients improved, 20% stayed the same, and 11% worsened postsurgery. Two patients died, yielding a mortality of 4.3%. CONCLUSION: Using the less-invasive resection technique for piecemeal BSCM removal, in appropriately selected patients, has yielded comparable to improved patient outcomes over existing large series. In our experience, lateral, anterolateral, and posterolateral approaches are favorable over direct midline (dorsal or ventral) approaches. A thorough understanding of brain-stem safe-entry zones, in conjunction with appropriate approach selection, is key to a good outcome in challenging cases.

Cranial Chordoma: A New Preoperative Grading System.

BACKGROUND: Chordomas are rare but challenging neoplasms involving the skull base. A preoperative grading system will be useful to identify both areas for treatment and risk factors, and correlate to the degree of resection, complications, and recurrence. OBJECTIVE: To propose a new grading system for cranial chordomas designed by the senior author. Its purpose is to enable comparison of different tumors with a similar pathology to clivus chordoma, and statistically correlate with postoperative outcomes. METHODS: The numerical grading system included tumor size, site of the tumor, vascular encasement, intradural extension, brainstem invasion, and recurrence of the tumor either after surgery or radiotherapy with a range of 2 to 25 points; it was used in 42 patients with cranial chordoma. The grading system was correlated with number of operations for resection, degree of resection, number and type of complications, recurrence, and survival. RESULTS: We found 3 groups: low-risk 0 to 7 points, intermediate-risk 8 to 12 points, and high-risk ≥13 points in the grading system. The 3 groups were correlated with the following: extent of resection (partial, subtotal, or complete; P < .002); number of operative stages to achieve removal (P < .014); tumor recurrence (P = .03); postoperative Karnofsky Performance Status (P < .001); and with successful outcome (P = .005). The grading system itself correlated with the outcome (P = .005). CONCLUSION: The proposed chordoma grading system can help surgeons to predict the difficulty of the case and know which areas of the skull base will need attention to plan further therapy.

Transpetrosal approach to petro-clival meningioma.

A 38-year-old woman had a 3-week gradual onset of right-sided weakness in the upper and lower extremities. MRI showed a large left petro-clival meningioma encasing the basilar and left superior cerebellar artery and compressing the brainstem. A posterior transpetrosal approach, with a left temporal and retrosigmoid craniotomy and mastoidectomy, was performed. The tumor was removed in a gross-total resection with questionable remnants adherent to the brainstem. Intraoperative partial iatrogenic injury to the left oculomotor nerve was repaired with fibrin glue. Postoperatively, the hemiparesis improved, and the patient was discharged to the rehabilitation center with left oculomotor and abducens palsies. A postoperative MRI scan showed complete resection of tumor with no remnants on the brainstem. A 6-month follow-up examination showed complete resolution of motor symptoms and complete recovery of cranial nerve (CN) palsies affecting CN III and CN VI. The video can be found here: https://youtu.be/vOu6YFA8uoo .

Cerebral Revascularization for Aneurysms in the Flow-Diverter Era.

BACKGROUND: Cerebral bypass has been an important tool in the treatment of complex intracranial aneurysms. The recent advent of flow-diverting stents (FDS) has expanded the capacity for endovascular arterial reconstruction. OBJECTIVE: We investigated how the advent of FDS has impacted the application and outcomes of cerebral bypass in the treatment of intracranial aneurysms. METHODS: We reviewed a consecutive series of cerebral bypasses during aneurysm surgery over the course of 10 years. FDS were in active use during the last 5 years of this series. We compared the clinical characteristics, surgical technique, and outcomes of patients who required cerebral bypass for aneurysm treatment during the preflow diversion era (PreFD) with those of the postflow diversion era (PostFD). RESULTS: We treated 1061 aneurysms in the PreFD era (from July 2005 through June 2010) and 1348 in the PostFD era (from July 2010 through June 2015). Eighty-five PreFD patients (8%) and 45 PostFD patients (3%) were treated with cerebral bypass. PreFD patients had better baseline functional status compared to PostFD patients with average preoperative modified Rankin Scale score of 0.55 in PreFD and 1.18 in PostFD. CONCLUSION: After the introduction of FDS, cerebral bypass was performed in a lower proportion of patients with aneurysms. Patients selected for bypass in the flow-diverter era had worse preoperative modified Rankin Scale scores indicating a greater complexity of the patients. Cerebral bypass in well-selected patients and revascularization remains an important technique in vascular neurosurgery. It is also useful as a rescue technique after failed FDS treatment of aneurysms.

Endonasal management of pediatric congenital transsphenoidal encephaloceles: nuances of a modified reconstruction technique. Technical note and report of 3 cases.

OBJECTIVE Congenital transsphenoidal encephaloceles are rare malformations, and their surgical treatment remains challenging. This paper reports 3 cases of transsphenoidal encephalocele in 8- to 24-month-old infants, who presented mainly with airway obstruction, respiratory distress, and failure to thrive. METHODS The authors discuss the surgical management of these lesions via a minimally invasive endoscopic endonasal approach, as compared with the traditional transcranial and transpalatal approaches. A unique endonasal management algorithm for these lesions is outlined. The lesions were repaired with no resection of the encephalocele sac, and the cranial base defects were reconstructed with titanium mesh plates and vascular nasoseptal flaps. RESULTS Reduction of the encephalocele and reconstruction of the skull base was successfully accomplished in all 3 cases, with favorable results. CONCLUSIONS The described endonasal management algorithm for congenital transsphenoidal encephaloceles is a safe, viable alternative to traditional transcranial and transpalatal approaches, and avoids much of the morbidity associated with these open techniques.

Planum Sphenoidale and Tuberculum Sellae Meningiomas: Operative Nuances of a Modern Surgical Technique with Outcome and Proposal of a New Classification System.

BACKGROUND: The resection of planum sphenoidale and tuberculum sellae meningiomas is challenging. A universally accepted classification system predicting surgical risk and outcome is still lacking. OBJECTIVES: We report a modern surgical technique specific for planum sphenoidale and tuberculum sellae meningiomas with associated outcome. A new classification system that can guide the surgical approach and may predict surgical risk is proposed. METHODS: We conducted a retrospective review of the patients who between 2005 and March 2015 underwent a craniotomy or endoscopic surgery for the resection of meningiomas involving the suprasellar region. Operative nuances of a modified frontotemporal craniotomy and orbital osteotomy technique for meningioma removal and reconstruction are described. RESULTS: Twenty-seven patients were found to have tumors arising mainly from the planum sphenoidale or the tuberculum sellae; 25 underwent frontotemporal craniotomy and tumor removal with orbital osteotomy and bilateral optic canal decompression, and 2 patients underwent endonasal transphenoidal resection. The most common presenting symptom was visual disturbance (77%). Vision improved in 90% of those who presented with visual decline, and there was no permanent visual deterioration. Cerebrospinal fluid leak occurred in one of the 25 cranial cases (4%) and in 1 of 2 transphenoidal cases (50%), and in both cases it resolved with treatment. There was no surgical mortality. CONCLUSION: An orbitotomy and early decompression of the involved optic canal are important for achieving gross total resection, maximizing visual improvement, and avoiding recurrence. The visual outcomes were excellent. A new classification system that can allow the comparison of different series and approaches and indicate cases that are more suitable for an endoscopic transsphenoidal approach is presented.

Bypasses and reconstruction for complex brain aneurysms.

Microsurgery for brain aneurysms is a current relevant technique, as advances in endovascular and stent-assisted coiling have not solved many of the difficulties inherent in the management of complex brain aneurysms. The following review highlights the importance of microsurgical bypass techniques for the management of complex cerebrovascular aneurysms and emphasizes, through two clinical cases, the technical difficulties and indications for bypass surgery. These cases demonstrate that in selected scenarios, bypass microsurgery still offers the only viable treatment for complex aneurysms.