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Cristian Gragnaniello and Kevin A. Seex

Lateral interbody cages have proven useful in lumbar fusion surgery. Spanning both lateral cortical rims while sparing the anterior longitudinal ligament, they restore disc height, improve coronal balance and add stability. The standard approach to their insertion is 90 degrees lateral transpsoas which is bloodless compared to other techniques of interbody cage insertion but requires neuro-monitoring and at L4/5 can be difficult because of iliac crest obstruction or an anterior plexus position. The oblique muscle-splitting approach with the patient in a lateral position, remains retroperitoneal, and on the left side enters the disc space through a window between psoas and the common iliac vein. Reports of this approach are few and none previously have described how to use the large lateral-type cages so effective at restoring spinal alignment. In this video we demonstrate our technique of anterior to psoas fusion of the lumbar spine with a retroperitoneal approach and gentle retraction of the psoas muscle.

The video can be found here:

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Skull base tumor model

Laboratory investigation

Cristian Gragnaniello, Remi Nader, Tristan van Doormaal, Mahmoud Kamel, Eduard H. J. Voormolen, Giovanni Lasio, Emad Aboud, Luca Regli, Cornelius A. F. Tulleken and Ossama Al-Mefty


Resident duty-hours restrictions have now been instituted in many countries worldwide. Shortened training times and increased public scrutiny of surgical competency have led to a move away from the traditional apprenticeship model of training. The development of educational models for brain anatomy is a fascinating innovation allowing neurosurgeons to train without the need to practice on real patients and it may be a solution to achieve competency within a shortened training period. The authors describe the use of Stratathane resin ST-504 polymer (SRSP), which is inserted at different intracranial locations to closely mimic meningiomas and other pathological entities of the skull base, in a cadaveric model, for use in neurosurgical training.


Silicone-injected and pressurized cadaveric heads were used for studying the SRSP model. The SRSP presents unique intrinsic metamorphic characteristics: liquid at first, it expands and foams when injected into the desired area of the brain, forming a solid tumorlike structure. The authors injected SRSP via different passages that did not influence routes used for the surgical approach for resection of the simulated lesion. For example, SRSP injection routes included endonasal transsphenoidal or transoral approaches if lesions were to be removed through standard skull base approach, or, alternatively, SRSP was injected via a cranial approach if the removal was planned to be via the transsphenoidal or transoral route. The model was set in place in 3 countries (US, Italy, and The Netherlands), and a pool of 13 physicians from 4 different institutions (all surgeons and surgeons in training) participated in evaluating it and provided feedback.


All 13 evaluating physicians had overall positive impressions of the model. The overall score on 9 components evaluated—including comparison between the tumor model and real tumor cases, perioperative requirements, general impression, and applicability—was 88% (100% being the best possible achievable score where the evaluator strongly agreed with the proposed factor). Individual components had scores at or above 80% (except for 1). The only score that was below 80% was related to radiographic visibility of the model for adequate surgical planning (score of 74%). The highest score was given to usefulness in neurosurgical training (98%).


The skull base tumor model is an effective tool to provide more practice in preoperative planning and technical skills.

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Anthony M. T. Chau, Lileane L. Xu, Rhys van der Rijt, Johnny H. Y. Wong, Cristian Gragnaniello, Ralph E. Stanford and Ralph J. Mobbs


Autologous bone from the iliac crest is commonly used for spinal fusion. However, its use is associated with significant donor site morbidity, especially pain. Reconstructive procedures of the iatrogenic defect have been investigated as a technique to alleviate these symptoms. The goal of this study was to assess the effects of reconstruction versus no reconstruction following iliac crest harvest in adults undergoing spine surgery.


The authors searched the Cochrane Central Register of Controlled Trials (The Cochrane Library 2011, Issue 4); MEDLINE (1948–Oct 2011); EMBASE (1947–Oct 2011); and the reference lists of articles. Randomized controlled trials (RCTs) or nonrandomized controlled trials (NRCTs) were included in the study. Two independent reviewers selected the studies, extracted data using a standardized collection form, and assessed for risk of bias.


Three RCTs (96 patients) and 2 NRCTs (82 patients) were included. These had a moderate to high risk of bias. The results suggest that iliac crest reconstruction may be useful in reducing postoperative pain, minimizing functional disability, and improving cosmesis. No pattern of other clinical, radiological, or resource outcomes was identified.


Although the available evidence is suboptimal, this systematic review supports the notion that iliac crest reconstruction following harvest for spinal fusion may reduce postoperative pain, minimize functional disability, and improve cosmesis.

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Cristian Gragnaniello, Kevin A. Seex, Lukas G. Eisermann, Matthew H. Claydon and Gregory M. Malham

The authors report on 2 cases of anterior dislocation of the Maverick lumbar disc prosthesis, both occurring in the early postoperative period. These cases developed after experience with more than 50 uneventful cases and were therefore thought to be unrelated to the surgeon's learning curve. No similar complications have been previously reported.

The anterior Maverick device has a ball-and-socket design made of cobalt-chromium-molybdenum metal plates covered with hydroxyapatite. The superior and inferior endplates have keels to resist translation forces.

The patient in Case 1 was a 52-year-old man with severe L4–5 discogenic pain; and in Case 2, a 42-year-old woman with disabling L4–5 and L5–S1 discogenic back pain. Both patients were without medical comorbidities and were nonsmokers with no risk factors for osteoporosis. Both had undergone uneventful retroperitoneal approaches performed by a vascular access surgeon. Computed tomography studies on postoperative Day 2 confirmed excellent prosthesis placement. Initial recoveries were uneventful. Two weeks postoperatively, after stretching (extension or hyperextension) in bed at home, each patient suffered the sudden onset of severe abdominal pain with anterior dislocation of the Maverick prosthesis. The patients were returned to the operating room and underwent surgery performed by the same spinal and vascular surgeons. Removal of the Maverick prosthesis and anterior interbody fusion with a separate cage and plate were performed. Both patients had recovered well with good clinical and radiological recovery at the 6- and 12-month follow-ups.

Possible causes of the anterior dislocation of the Maverick prosthesis include the following: 1) surgeon error: In both cases the keel cuts were neat, and early postoperative CT confirmed good placement of the prosthesis; 2) equipment problem: The keel cuts may have been too large because the cutters were worn, which led to an inadequate press fit of the implants; 3) prosthesis fault: Both plates of the dislocated implants looked normal and manufacturer analysis reported no fault; 4) patient factors: Both dislocations happened early in the postoperative period, after hyperextension of the spine while the patient was supine in bed. Bracing would not have reduced hyperextension.

Dislocation of a lumbar spinal implant represents a life-threatening complication and should therefore be considered and recognized early. Radiographic and CT studies of both the lumbar spine (for prosthesis) and the abdomen (for hematoma) should be performed, as should CT angiography (for vessel damage or occlusion).

Any anterior lumbar revision surgery is hazardous, and it is strongly advisable to have a vascular surgeon scrubbed. In cases of dislocation or extrusion of a lumbar interbody prosthesis, the salvage revision strategy is fusing the segment via the same anterior approach.

Surgeons should be aware of the risk of anterior dislocation of the Maverick prosthesis. Keel cutters should be regularly checked for sharpness, as they may be implicated in the loosening of implants. Patients and their physical therapists should also avoid lumbar hyperextension in the early postoperative period.