Degenerative foraminal stenosis of the cervical spine can lead to cervicobrachial neuralgias. Computed tomography (CT)-scan assists in the diagnosis and evaluation of foraminal stenosis. The main objective of this study is to determine the bony dimensions of the cervical intervertebral foramen and to identify which foraminal measurements are most affected by degenerative disorders of the cervical spine. These data could be applied to the surgical treatment of this pathology, helping surgeons to focus on speci c areas during decompression procedures. MethodsA descriptive study was conducted between two groups: an asymptomatic one (young people with no evidence of degenerative cervical spine disorders) and a symptomatic one (experiencing cervicobrachial neuralgia due to degenerative foraminal stenosis). Using CT scans, we determined a method allowing measurements of the following foraminal dimensions: foraminal height (FH), foraminal length (FL), foraminal width in its lateral part ((UWPP, MWPP and IWPP (respectively Upper, Medial and Inferior Width of Pedicle Part)) and medial part (UWMP, MWMP and IWMP (respectively Upper, Medial and Inferior Width

Purpose: Because of its super cial location in the dorsal regions of the scalp, the greater occipital nerve (GON) can be injured during neurosurgical procedures, resulting in post-operative pain and postural disturbances. The aim of this work is to specify the course of the GON and how its injuries can be avoided while performing posterior fossa approaches.Methods: This study was carried out at the department of anatomy in Bordeaux University. 4 specimens were dissected to study the GON course. Posterior fossa approaches (midline suboccipital, paramedian suboccipital, retrosigmoid and petrosal) were performed on 4 other specimens in order to assess potential risks of GON injuries.Results: The GON runs around the obliquus capitis inferior (100%), crosses the semispinalis capitis (100%) and the trapezius (75%) or its aponeurosis (25%). Direct GON injuries can be seen in paramedian suboccipital approaches. Stretching of the GON can occur in midline suboccipital and paramedian suboccipital approaches. We found no evidence of direct or indirect GON injury in retrosigmoid or petrosal approaches. Conclusion:Our study provides interesting data regarding the risk GON injury in posterior fossa approaches. Direct GON injuries in paramedian suboccipital approaches can be avoided with careful dissection. Placing retractors in contact with the periosteum and performing a minimal retraction may help to avoid excessive GON stretching in midline suboccipital and paramedian suboccipital approaches. Furthermore, incision for retrosigmoid approaches should be as lateral as possible and not too caudal. Finally, avoiding extreme patient positioning reduces the risk of GON stretching in all approaches.

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Purpose: Spinal osteotomies performed to treat xed spinal deformities are technically demanding and associated with a high complications rate. The main purpose of this study was to analyze complications and their risk factors in spinal osteotomies performed for xed sagittal imbalance from multiple etiologies.Methods: The study consisted of a blinded retrospective analysis of prospectively collected data from a large multicentre cohort of patients who underwent 3-columns (3C) spinal osteotomy, between january 2010 and january 2017. Clinical and radiological datas were compared pre and post operatively. Complications and their risks factors were analyzed.Results: Two hundred eighty-six 3C osteotomies were performed in 273 patients. At 1year follow-up, both clinical (VAS pain, ODI and SRS-22 scores) and radiological (SVA, SSA, loss of lordosis and pelvic version) parameters were signi cantly improved (p<0.001). A total of 164 patients (59.2%) experienced at least 1 complication (277 complications). Complications-free survival rates was only 30% at 5 years.Most of those were mechanical (35.2%), followed by general (17.6%), surgical site infection (17.2%) and neurological (10.9%). Pre-operative neurological status (RR=2.3 [1.32-4.00]), operative time (+19% of risk each additional hour) and combined surgery (RR=1.76 [1.08-2.04]) were assessed as risk factors for overall complication (p<0.05). The use of Patient-speci c rods appeared to be signi cantly associated with less overall complications (RR=0.5 [0.29-0.89]) (p=0.02).Conclusion: Spinal 3C osteotomies were e cient to improve both clinical and radiological parameters despite high rates of complication. Efforts should be made to reduce operative time which appears to be the strongest predictive risk factor for complication.

Purpose The respective effects of direct and indirect decompression in the clinical outcome after anterior cervical disc fusion (ACDF) is still debated. The main purpose of this study was to determine whether the height of the implants was associated with postoperative foraminal height and volume, and with clinical improvement in patients suffering from cervico-brachial neuralgias due to degenerative foraminal stenosis. Methods We conducted a prospective follow-up of patients who underwent ACDF for cervicobrachial neuralgias due to degenerative foraminal stenosis. Patient had filled auto questionnaires (Neck Disability Index (NDI), Visual Analog Scales (VAS) for cervical and radicular pain) and performed a CT-scan pre and post-operatively. Disc height, foraminal height and foraminal volumes were measured pre and post operatively. Results 37 cervical disc fusions were successfully performed in 20 patients, with a total of 148 foramina studied. A significant improvement in the 3 scores was observed at 3 months postoperatively (p < 0.001). We found a significant improvement in every radiological parameter, with a significant increase in disc height, foraminal height and foraminal volume being respectively + 3,22mm (p < 0,001), + 2,12mm (p < 0,001) and + 54mm3 (p < 0,001). Increase in disc height was significantly associated with increase in foraminal height (p < 0,001) and foraminal volume (p < 0,001). Increase in foraminal height was significantly correlated with foraminal volume (p < 0,001) and with improvement in NDI score (p:0,037). Considering all those findings, our study suggests that indirect decompression helps in clinical improvement after ACDF. Conclusion This study provides interesting data regarding the clinical benefit of indirect decompression in ACDF performed for cervicobrachial neuralgias.