Ultrasound-Guided Dry Needling of the Healthy Rat Supraspinatus Tendon Elicits Early Healing Without Causing Permanent Damage

Overuse-induced tendinopathy is highly prevalent in the general population. Percutaneous fenestration, or dry needling, techniques have been increasing in popularity, but despite their current use, there are no controlled laboratory studies to provide fundamental support for this practice. The objective of this study was to establish a model for percutaneous needling of the rat supraspinatus tendon using ultrasound guidance and to evaluate the biological response of needling healthy tendon. A total of 44 male Sprague-Dawley rats (477 ± 39 g) were used to evaluate the effect of dry needling on healthy supraspinatus tendon properties. Ten rats were reserved as un-needled control animals, and the remaining animals underwent either mild or moderate bilateral needling protocols and were sacrificed at 1 or 6 weeks post-needling (n = 8-10/group). Color Doppler ultrasound imaging was performed to analyze blood flow within the tendon. Histological and immunohistochemical analyses were used to determine cellular, inflammatory, and extracellular matrix properties of the tissue. Finally, quasi-static tensile mechanical analysis was performed to obtain viscoelastic, structural, and material properties to evaluate the tendon healing outcome. Data were tested for normality, and then two-way analysis of variance tests were performed followed by post hoc tests for multiple comparisons. Both the mild and moderate needling groups caused a transient healing response at early time points as shown by a statistically significant (p < 0.05) reduction in mechanical properties, and increase in blood flow, inflammation, and production of collagen III and glycosaminoglycans as compared to the control. Furthermore, mild needling properties returned to or exceeded pre-needling values at the 6-week time point. Clinical significance: Needling the rat supraspinatus tendon is a feasible technique that causes a transient healing response followed by a return to, or improvement of, normal tendon properties, indicating potential applicability in understanding the effects of current practices utilizing dry needling of tendons in humans. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 37:2035-2042, 2019.

Recurrence of a symptomatic spinal intradural arachnoid cyst 29 years after fenestration

Symptomatic arachnoid cysts are relatively rare, and no case reports have described recurrence of such cysts almost 30 years after surgery. We herein report a case in which a symptomatic intradural arachnoid cyst recurred 29 years after fenestration of the primary lesion. The patient was a 64-year-old woman who presented with paralysis of the left lower limb. She had undergone surgical treatment for an intradural arachnoid cyst at the T12 level 29 years previously. Magnetic resonance imaging (MRI) revealed an intradural mass at the T12–L1 level. The mass was compressing the spinal cord and cauda equina. Its localization and shape on MRI were similar to those of the primary cyst 29 years previously. Partial resection was performed under a diagnosis of a recurrent intradural arachnoid cyst. After surgery, the patient’s left lower limb paralysis improved. The pathological findings were suggestive of an intradural arachnoid cyst. The MRI findings 29 years previously provided useful information. The possibility of very late recurrence should be considered in patients who undergo surgical removal of intradural arachnoid cysts.

Hybrid versus in vitro fenestration for preserving the left subclavian artery in patients undergoing thoracic endovascular aortic repair with unfavorable proximal landing zone

Purpose

To compare hybrid and in vitro fenestration procedures for preserving the left subclavian artery in thoracic endovascular aortic repair (TEVAR) with unfavorable proximal landing zone.

Methods

Retrospective comparison of data from 49 consecutive patients who underwent left subclavian artery revascularization during TEVAR by either hybrid or fenestration approaches from January 2015 to March 2018. Procedural duration, and 30-day rates of procedural success, mortality and complications (endoleaks, cerebral infarction, spinal cord ischemia, left arm ischemic symptoms, and delirium) were compared.

Results

For hybrid procedure ( n = 32) vs. fenestration ( n = 17) groups, which were age and gender matched: procedural success rate was 100%, with significantly longer procedural duration (248.4 ± 40.9 vs. 60.6 ± 16.8 min; t = –22.653, P = 0.000) and similar 30-day complication rate (18.8% vs. 11.8%; χ2 = 0.397, P = 0.529). At 12.7 ± 9.3 months’ follow-up, there were no cases of death, spinal cord ischemia, or other complications in either group.

Conclusions

In this retrospective, single-center comparison, both hybrid and in vitro fenestration approaches for reconstructing the left subclavian artery in TEVAR with unfavorable proximal landing zone appeared safe and effective, with shorter procedural duration for fenestration. Larger studies with longer term follow-up are warranted.

Intraoperative microsurgical anatomy of the anterior communicating artery complex harbouring an anterior cerebral territory aneurysm

Background

The vascular anatomy of the anterior communicating artery complex (ACAC), the most frequent site of occurrence of aneurysms, is complex and associated with many anatomical and morphological variations.

Aims

The aim of this study was to determine the anatomical variations of ACAC in the Indian population.

Setting and Design

This was an observational study.

Materials and Methods

Sixty-two patients of ACAC aneurysms were subjected to clipping, and intraoperative microsurgical details were analyzed.

Results

Twenty-two (35.48%) patients had anatomical and morphological variations that were more common on the right side. Right A1 was hypoplastic in 5 (8.06%), aplastic in 2 (3.22%), and tortuous in 1 (1.61%) patient. Left A1 was aplastic in 3 (4.83%), hypoplastic in 1 (1.61%) and prominent in 2 (3.22%) patients. One patient (1.61%) had a prominent left A2 segment and 2 (3.22%) had a prominent right A1 and A2 segment. Two patients (3.22%) had fenestration of the ACAC and 3 (4.83%) had the median artery of corpus callosum. The recurrent artery of Heubner was identified in only 44 (70.96%) patients, and in these patients, distinct anatomical variations were noted. Eleven patients were found to present with a parent vessel anomaly, having a total of 23 (mean, 2.09) perforators arising from ACAC, whereas those without a parent vessel anomaly had a total of 57 (mean, 1.11) perforators. This difference was statistically significant.

Conclusion

The ACAC region is the area of highest anatomical and morphological variability. This variability is even more exhaustive when associated with aneurysmal formation. A sound anatomical knowledge of the perforators and their preservation during the surgical management of the ACAC is of paramount importance for ensuring a good clinical outcome of patients.

Comparison of the fenestrated and non-fenestrated Fontan procedures: A meta-analysis

BACKGROUND

The benefits of fenestration for patients undergoing Fontan procedure seem controversial at early and late postoperative stages.

OBJECTIVE

We aimed to compare the outcomes between the fenestrated and non-fenestrated Fontan procedures.

METHODS

Studies comparing the fenestrated and non-fenestrated Fontan procedures were identified by searching the PubMed, EMBASE, and Cochrane Library databases until July 2018. The assessed variables included postoperative oxygen saturation (SaO2), pulmonary artery pressure, mortality, cardiopulmonary bypass (CPB) time, ventilation time, intensive care unit stay, hospital stay, chest tube duration, protein-losing enteropathy, arrhythmia, and other follow-up outcomes including reintervention, stroke/thrombosis, and peak oxygen consumption. A random-effect/fixed-effect model was used to summarize the estimates of the mean difference (MD)/odds ratio (OR) with 95% confidence interval (CI). Subgroup analysis stratified by early and late outcomes was performed.

RESULTS

A total of 1929 Fontan patients from 14 studies were included. The early postoperative SaO2 was lower with fenestration than without fenestration (MD -2.52, 95% CI -4.16 to -0.87, P <.05); however, the late postoperative SaO2 showed no difference between the 2 approaches. The CPB time was shorter without fenestration than with fenestration (MD 10.72, 95% CI 2.54-18.9, P <.05); however, the incidence of arrhythmia was lower with fenestration than without fenestration (OR 0.43, 95% CI 0.25-0.75, P <.05). Other variables showed no significant differences between the 2 approaches in Fontan patients.

CONCLUSION

Fenestration appears to result in a lower incidence of arrhythmia but with a longer CPB time and lower early SaO2. Other outcomes are comparable between the 2 approaches.

Middle cerebral artery fenestration: Thromboembolic and hemorrhagic complications

Cerebral artery fenestrations are rare anatomical variants usually detected incidentally on cross-sectional imaging or cerebral angiography. Although considered benign findings, many reports have described their association with vascular abnormalities such as aneurysms or arteriovenous malformations, and to a lesser extent with ischemic or hemorrhagic complications. We report a case of middle cerebral artery fenestration associated with subarachnoid hemorrhage and middle cerebral artery thrombosis. To our knowledge, there has been no prior report of middle cerebral artery fenestration with a similar presentation.

Likelihood of needing facial bone augmentation in the anterior maxilla of Chinese Asians: A cone beam computed tomography virtual implant study

BACKGROUND

The perfect position and axis of an implant is often limited by the morphology of the alveolar ridge, especially in Asians.

PURPOSE

The aim of this study was to investigate the frequency at which ideal implant placement position in the anterior maxilla of Chinese Asians would require facial bone augmentation given by an initial facial bone profile.

MATERIALS AND METHODS

Implants were virtually placed in 303 sites without tooth loss in the anterior maxilla. The incidence and characters of implant facial plate fenestration were analyzed. If there was no facial fenestration, the thinnest buccal plate (TB) amount adjacent to the implant was measured and recorded.

RESULTS

A total of 79 (26.07%) sites showed fenestrations. The mean length, width, and area of exposure in the fenestration sites were 2.94 ± 1.67 mm, 1.52 ± 0.97 mm, and 2.84 ± 3.13 mm² , respectively. In the nonfenestrated sites, the TB of facial bone around the virtual implants was 1.10 ± 0.78 mm. Among the 224 nonfenestrated sites, 126 sites had a TB of less than 1 mm.

CONCLUSIONS

It can be concluded that the initial facial bone profile should be considered when designing restorations and choosing an optimal implant position in the anterior maxilla.

Plaque Distribution of Basilar Artery Fenestration by 3D High-Resolution MR Vessel Wall Imaging

The association between fenestrations and neurovascular pathology is not well defined. The morphology of vessel wall plays an important role in the development of neurovascular pathology. We sought to explore the plaque distribution around basilar artery fenestration (BAF) by three-dimensional high-resolution MR vessel wall imaging (3D HRMRI). Patients with BAF on 3D HRMRI images were enrolled. All cross-sectional slices of basilar arteries were assessed and categorized based on the location of fenestration as proximal segment, in-bifurcation segment, and distal segment. Furthermore, plaques in the in-bifurcation segment were classified according to their orientation being centered on the lateral, interior, dorsal, or ventral wall of the vessel. In all, 12 cases with BAF involving 661 cross-sectional image slices in entire basilar arteries were included. Plaques were found in 190 image slices, with the distribution of 41 slices in the proximal segment, 144 slices in the in-bifurcation segment and 67 slices in the distal segment. Plaques were found more frequently in the proximal and in-bifurcation segments than in the distal segment (P < 0.001), but there was no statistical difference between the proximal and in-bifurcation segment (P = 0.11). In the in-bifurcation segment, plaques were more frequently located at the lateral (50.0%) than other interior (16.0%), dorsal (21.0%), and ventral (13.0%) wall (P < 0.001).Plaques of BAF tend to locate in the proximal and in-bifurcation segments, especially at the lateral wall of the in-bifurcation segment.

Endovascular management of a ruptured aneurysm associated with distal PICA fenestration

Fenestrations are rare but well-known arterial anatomic variations in which a segment of artery divides into two parallel channels that reunite distally. Although fenestrations as such are asymptomatic, they have gained clinical significance because of their association with aneurysms and other intracranial vascular pathologies. Here we present a 35-year-old woman with history of sudden severe occipital headache and vomiting. Imaging revealed a ruptured aneurysm in the distal posterior inferior cerebellar artery arising from one of the limbs of the fenestration. The aneurysm was successfully managed by coiling, and the patient made complete recovery without neurological sequelae.

Hybrid Aortic Arch Repairs

Hybrid aortic arch repair (HAAR) consists of thoracic stent-graft repair and procedures to maintain cerebral blood flow. Several hybrid techniques have been used, including arch artery debranching, parallel graft technique, fenestration or branching of endograft, or a combination of these. We provided an overview of HAAR by presenting literature reviews as well as our clinical experience. The experience consisted of 172 patients who had undergone HAAR. The 30-day mortality was 3% (5/172). Persistent neurologic deficits occurred in 7 patients (4%), respiratory failure in 5 (3%), de novo aortic dissection in 3 and spinal cord injury in 2. 17% of the patients experienced type Ia endoleak. Seventeen patients required redo thoracic endovascular aortic repair. Fifty-six late deaths occurred during the follow-up period, including aortic-related death in 9 patients. In conclusion, hybrid arch debranching repair should be performed for elderly or high-surgical-risk patients. However, refining techniques and device technology is likely to reduce late endograft-related events. (This is a translation of Jpn J Vasc Surg 2018; 27: 385-391.).

Transungual Delivery of Ciclopirox Is Increased 3⁻4-Fold by Mechanical Fenestration of Human Nail Plate in an In Vitro Model

Onychomycosis is a fungal infection of nails that is widespread and difficult to treat because of the impermeable nature of human nails. Topically applied anti-fungal agents cannot penetrate this structure, and treatment regimens often resort to systemic antifungals with concomitant side effects. One recent clinical study suggested that mechanical fenestration of the nail using an intelligent nail drill might be a possible solution to this problem. In this work, an in vitro model of the transungual delivery of antifungal agents is presented, which utilizes real nail tissue and an inline flow system. This system was deployed to measure transungual delivery of ciclopirox and determined that nail fenestration improved drug delivery by 3–4-fold after 42 days. This study bolsters the argument that nail fenestration should be accepted as a pretreatment for onychomycosis and offers a way of evaluating new drugs or formulations designed to combat this condition.

An infrequent clinical case of mucosal fenestration: Treated with an interdisciplinary approach and regenerative therapy

Mucosal fenestration is a clinical finding in which a portion of the tooth root is denuded of the overlying alveolar bone and gingiva or oral mucosa, thus exposing the root to the oral cavity. If left untreated, they may be a source of infection by giving entry to oral pathogen, leading to further progression of periodontal disease. Depending on their site of presence, they may also be a reason of esthetic concern to some patients. This paper reports one such infrequent case of mucosal fenestration of lower incisor region that was well treated by an interdisciplinary approach and regenerative therapy.

Fenestrations control resting-state block of a voltage-gated sodium channel

Potency of drug action is usually determined by binding to a specific receptor site on target proteins. In contrast to this conventional paradigm, we show here that potency of local anesthetics (LAs) and antiarrhythmic drugs (AADs) that block sodium channels is controlled by fenestrations that allow drug access to the receptor site directly from the membrane phase. Voltage-gated sodium channels initiate action potentials in nerve and cardiac muscle, where their hyperactivity causes pain and cardiac arrhythmia, respectively. LAs and AADs selectively block sodium channels in rapidly firing nerve and muscle cells to relieve these conditions. The structure of the ancestral bacterial sodium channel Na_VAb, which is also blocked by LAs and AADs, revealed fenestrations connecting the lipid phase of the membrane to the central cavity of the pore. We cocrystallized lidocaine and flecainide with Na_vAb, which revealed strong drug-dependent electron density in the central cavity of the pore. Mutation of the contact residue T206 greatly reduced drug potency, confirming this site as the receptor for LAs and AADs. Strikingly, mutations of the fenestration cap residue F203 changed fenestration size and had graded effects on resting-state block by flecainide, lidocaine, and benzocaine, the potencies of which were altered from 51- to 2.6-fold in order of their molecular size. These results show that conserved fenestrations in the pores of sodium channels are crucial pharmacologically and determine the level of resting-state block by widely used drugs. Fine-tuning drug access through fenestrations provides an unexpected avenue for structure-based design of ion-channel-blocking drugs.

Fenestrated ASD device "angioplasty": How to adjust a "pop-off" mechanism when needed

We report on three cases of atrial septal defect (ASD) closure where a handmade fenestration had to be modified after device implantation. Two patients suffered from left ventricular diastolic dysfunction and one had severe pulmonary arterial hypertension. Amplatzer ASD occluder fenestration was created in all patients. Devices were implanted using an "over-the-wire" implantation technique. Due to a sub-optimal hemodynamic result, fenestration was upsized by using a new technique.

Fenestrated Endovascular Abdominal Aortic Aneurysm Repair

In order to offer more patients a durable endovascular abdominal aortic aneurysm repair parallel, branched, and fenestrated grafts have been utilized. These treatments aim at increasing the quality of the proximal aortic graft landing zone by incorporating the healthy aortic neck at the renal and visceral arteries. Fenestrated endovascular aneurysm repair has provided a standardized and approved treatment option for patients who may otherwise not be candidates for endovascular repair. We discuss the technique of fenestrated endovascular aneurysm repair and the challenges involved in selecting the appropriate patients.

Resection of an extensive thoracic arachnoid cyst via less-invasive targeted laminoplasties

OBJECTIVE

Spinal arachnoid cysts are a known cause of spinal cord compression. When symptomatic, treatment of choice entails laminectomies over the length of the cyst in order to achieve complete cyst removal and fenestration.

METHODS

A 60-year-old woman presented with a one-year history of progressive pain between the shoulder blades, exacerbated by sitting up or standing, and relieved by lying supine. MRI imaging revealed a T3-T7 dorsal intradural arachnoid cyst. Due to extant spinal deformity and medical comorbidity, the decision was made to proceed with selective laminoplasties at the superior and inferior limits of the cyst.

RESULTS

After the dura was opened to reveal the margins, the cyst was sharply fenestrated and drained. Irrigation was passed through the cyst to ensure open communication, and a lumbar drain catheter was passed from the inferior to superior margin. The catheter was removed before closure. Postoperatively, MRI of the thoracic spine revealed decompression of the spinal cord and the patient noticed improvement in her symptoms. At 7-month follow-up, the patient remained free of symptoms and MRI demonstrated near-complete resolution of the cyst.

CONCLUSION

Although open exposure and complete resection are considered the treatment of choice for spinal arachnoid cysts, cyst fenestration through selective bony windows at the margins of the cyst represents a viable, less invasive alternative approach to effective cyst decompression, and can be considered in patients in whom a full exposure would be prohibitive.

Variations of the Transverse Sinus: Review with an Unusual Case Report

The dural venous sinuses are venous channels in the cranium that drain blood and cerebrospinal fluid circulating from the brain into the vascular system via the internal jugular veins. The transverse sinus is a dural venous sinus present in the posterior aspect of the cranium. We report an unusual variant of this sinus with the presence of a fenestration at its proximal segment. We will review and discuss the background and the potential clinical relevance of this anatomical variation.

Successful endovascular recanalization of a partially occluded basilar artery fenestration

A 76-year-old man with a history of arterial hypertension, obstructive sleep apnea, dyslipidemia, family history of cardiovascular events, prestroke and overweight presented 90 minutes after acute onset of right-sided sensorimotor hemiparesis, hemiataxia and dysarthria (National Institutes of Health Stroke Scale (NIHSS) 9/42). Magnetic resonance imaging (MRI) revealed a pontine ischemia and MR angiography showed a thrombus in the middle to distal portion of the basilar artery. Owing to the location, an occlusion of one lumen of a fenestrated basilar artery was suspected. Fearing the risk of peripheral dislocation, intravenous thrombolysis was withheld after an interdisciplinary discussion and direct endovascular thrombectomy (Solitaire stent retriever) was successfully performed by passing the stent retriever specifically through the affected lumen and between the thrombus and the vascular wall, which would normally be avoided. Angiography after complete reperfusion (Thrombolysis in Cerebral Infarction grade 3) confirmed a fenestration in the middle to distal portion of the basilar artery where the thrombus was initially located (blue and green arrow). Follow-up MRI after 24 hours showed only minimal ischemic damage in the left pontine area, and the patient was discharged home with ambulatory physiotherapy for residual minimal gait disturbance (NIHSS 0).

SK-Hep1: not hepatocellular carcinoma cells but a cell model for liver sinusoidal endothelial cells

SK-Hep1 cells serve as a cell model of hepatocellular carcinoma and hepatocyte biology. However, SK-Hep1 cells are markedly different from normal hepatocytes and other hepatocellular carcinoma cells in their gene expression and protein levels. Furthermore, endothelial-specific makers and morphological characteristics are found in SK-Hep1 cells, indicating an endothelial origin. To confirm their cell phenotype, we investigated and compared the surface ultrastructure, endothelial function, and molecular markers of SK-Hep1 cells in vitro and in vivo. The results revealed that SK-Hep1 cells expressed endothelial-specific makers and exhibited the endothelial function of endocytosis and tubular formation. Capillary-like structures with CD31 expression were also observed in SK-Hep1 allografts in nude mice. Moreover, SK-Hep1 cells possessed fenestrae without diaphragms, consistent with liver sinusoidal endothelial cells, as seen by electron microscopy. In conclusion, SK-Hep1 cells would be better considered a cell model for liver sinusoidal endothelial cells instead of hepatocellular carcinoma cells.

Endovascular management of acute aortic dissection

Acute dissection of the thoracic aorta is a potentially life-threatening condition which requires collaborative treatment from multiple specialties for optimal patient outcomes. Dissections involving the ascending aorta and aortic arch have traditionally been managed entirely by surgery, while dissections beyond the arch vessels have most commonly been relegated to medical management. This algorithm has been undergoing a paradigm shift over the past two decades due to improvements in stent graft technology, better understanding of the hemodynamic interactions of the true and false lumen and their influence on organ and limb perfusion, and improvements in medical management and long term surveillance for dissection-related complications. This manuscript includes a brief discussion of the pathogenesis and etiology of dissection, followed by an in-depth review of the medical and endovascular techniques utilized to treat patients afflicted by this condition.

Laser Fenestration for Treatment of a Complicated Chronic Type B Aortic Dissection

We report a case of a complex chronic type B aortic dissection treated by thoracic endovascular aortic repair and laser fenestration of the false septum to preserve flow to branch vessels originating from both the true and false lumen. Dissections complicated by thoracoabdominal aneurysmal degeneration with critical organs being perfused by branches arising from both true and false lumens are rare and leave limited options for repair. Despite advancements in endovascular techniques, fenestration remains one of the only means of preserving flow to both the true and false lumens and thus was necessary in the management of our patient. This novel procedure allows complex aortic dissections to be addressed endovascularly, which increases the flexibility and management of this challenging problem that previously required an open repair with significant morbidity.

Reentry Devices for Lamella Neofenestration During Endovascular Aortic Repair of Chronic Type B Aortic Dissection

PURPOSE

To present a technique that creates a neofenestration in the dissecting lamella of chronic aortic dissections using standard or intravenous ultrasound (IVUS)-guided reentry devices.

TECHNIQUE

To create a neofenestration, a standard or IVUS-guided reentry device is deployed in either the true or false aortic lumen while a balloon is simultaneously inflated in the opposite lumen to stabilize the lamella, provide needle counterforce, and prevent displacement of the lamella away from the reentry needle. Once the lamella is perforated and a guidewire passed across the 2 lumens, progressive dilation of the neofenestration is performed to establish persistent communication.

CONCLUSION

The balloon-supported lamella neofenestration technique involving off-label application of two currently available reentry devices can be applied to endovascular treatment chronic aortic dissections. While the technique will definitely not become a standard of practice, it provides a safe, effective, and readily available option for endovascular management of those patients with complex chronic aortic dissections requiring bailout maneuvers or elective treatment.

Totally Percutaneous Fenestration via the "Cheese-Wire" Technique to Facilitate Endovascular Aneurysm Repair in Chronic Aortic Dissection

Here, we describe a totally percutaneous technique for longitudinal fenestration of a chronic dissection flap in the setting of endovascular aneurysm repair (EVAR), where the septum would otherwise preclude proper endograft sealing. This technique is demonstrated in a 65-year-old man with a history of open surgical repair of a Stanford type A aortic dissection, with a type B component that was managed nonoperatively. The patient developed aneurysmal degeneration of the infrarenal aorta during follow-up, and his anatomy was well suited for EVAR with the exception of a chronic dissection flap dividing the proximal seal zone. Using bilateral percutaneous access, a wire was passed through an existing fenestration in the septum from true to false lumen and snared from the contralateral side. Downward traction on this through-wire was then used as a "cheese-wire" to divide the septum longitudinally and clear it from the proximal fixation site. Removal of the septum provided an adequate proximal seal zone for the endograft, and standard infrarenal EVAR was then performed with a good technical result. Longitudinal fenestration using this technique is a useful adjunctive maneuver to facilitate EVAR in the setting of chronic aortic dissection and is safely achievable via a totally percutaneous approach.

Pure Endoscopic Management of Fourth Ventricle Arachnoid Cyst: Case Report and Literature Review

Arachnoid cysts (ACs) within the fourth ventricle are rare, and only a few cases have been reported in the literature. These are benign lesions within the arachnoid membrane, and they have been reported to occur in almost all locations where arachnoid is present. Different procedures have been performed to restore a normal cerebrospinal fluid dynamic and/or pressure, including shunting and partial or complete excision of the cyst by open microsurgery or endoscopic fenestration. We report the case of a fourth ventricle AC successfully treated using only endoscopic anterior trans-frontal cyst fenestration/marsupialization and standard third ventriculostomy. Clinical and technical features are discussed, along with the pertinent literature.

Reoperations Following Lumbar Spinal Canal Stenosis

In the current clinical scenario, restenosis following the primary surgical procedure for lumbar canal stenosis is being frequently noticed. A number of studies have evaluated the reoperation rates following different surgical procedures for lumbar canal stenosis. However, a dilemma still exists about the surgical procedures, associated comorbidities and reoperation rates. In this study, we have reviewed the existing literature for lumbar canal stenosis surgery and their reoperation rates. A PubMed search for all papers stating "reoperation after spinal stenosis," "revision surgery after spinal stenosis," and "reoperations and lumbar canal stenosis" were explored. A total of 440 publications were found, of which 23 publications were shortlisted. The existing literature on reoperation rates after surgery for lumbar canal stenosis was reviewed and analyzed. From the literature search, 29680 patients who underwent surgeries for spinal stenosis have been included in the review. 11.65% ± 4.25% of them underwent reoperations following the primary procedure with a followup period of 6.80 ± 3.90 years. Fenestration surgeries showed an average reoperation rate of 7.58% ± 5.29% in 8.28 ± 6.26 years followup as compared to laminectomy alone (12.70% ± 7.49%, 6.50 ± 2.12 years followup). Laminectomy with or without fusion showed a reoperation rate of 11.22% ± 4.25% in 6.00 ± 2.60 years followup period. The comparative results of these studies were however not significant. The causes of reoperation were multifactorial ranging from the type of procedure performed, associated comorbidities or smoking. Statistical data do not indicate the superiority of any particular type of surgery, which reduces the rate of reoperation. The causes for reoperation are inadequate decompression or instability. The literature does not give statistics for these complications in the papers. Smoking is an independent risk factor for revision surgery. Diabetes reduces the time interval between the initial surgery and the revision surgery. This review highlights the causes of reoperations in various lumbar stenosis surgeries, associated comorbidities and expected outcome.