Journal of Neurosurgery: Spine

The intradural contributions of the C-4 nerve rootlets have not been previously evaluated for their connections to the brachial plexus. The authors undertook a cadaveric study to evaluate the C-4 contributions to the upper trunk of the brachial plexus.

The posterior cervical triangles from 60 adult cadavers were dissected. All specimens that were found to have extradural C-4 contributions to the upper trunk of the brachial plexus were excluded from further study. In specimens found to have no extradural C-4 contributions to the brachial plexus a C1–T1 laminectomy was performed. Observations were made of any neural communications between adjacent spinal rootlets, specifically between C-4 and C-5.

Nine (15%) of the 60 sides were found to have extradural C-4 contributions to the upper trunk of the brachial plexus. These sides were excluded from further study. No specimen was found to have a postfixed brachial plexus. Of the remaining 51 sides, 11 (21.6%) were found to have intradural neural connections between C-4 and C-5 dorsal rootlets and 1 (1.96%) had a connection between the ventral roots of C-4 and C-5. Communications between these 2 adjacent dorsal cervical cord levels were of 3 types. Type I was a vertical communication between the more horizontally traveling dorsal roots. Type II was a forked communication between adjacent C-4 and C-5 dorsal rootlets. The Type III designation was applied to connections between ventral rootlets. Although communications were slightly more frequent on left sides, this did not reach statistical significance.

In ~ 20% of normally composed brachial plexuses (those with extradural contributions from only C5–T1) we found intradural C4–5 neural connections. Such variations may lead to misinterpretation of spinal levels in pathological conditions of the spinal axis and should be considered in surgical procedures of this region, such as rhizotomy.

Kỹ thuật ban đầu về ổn định atlantoaxial bằng các đinh vít vào khối bên C-1 và pars C-2 bao gồm cả cắt bỏ thần kinh C-2 để cung cấp đủ tầm nhìn và cầm máu trong quá trình đặt vít, đảm bảo cắt mài và nối khớp, ngăn ngừa đau dây thần kinh C-2 sau phẫu thuật. Tuy nhiên, việc thực hiện cắt bỏ thần kinh C-2 trong quy trình này vẫn còn gây tranh cãi, có thể do thiếu các nghiên cứu cụ thể xem xét nó có ảnh hưởng đến kết quả của bệnh nhân hay không. Mục tiêu của tác giả là đánh giá tác động phẫu thuật và lâm sàng của cắt bỏ thần kinh C-2 thường xuyên cùng với nối tầng đốt sống cổ-đầu bằng dụng cụ trong chuỗi liên tiếp các bệnh nhân cao tuổi với bất ổn cổ C1-C2.

44 bệnh nhân liên tiếp (tuổi trung bình 71 năm) đã thực hiện nối tầng C1-C2 bằng dụng cụ, bao gồm việc đặt vít khối bên C-1. Cắt bỏ thần kinh C-2 hai bên được thực hiện. Đánh giá lâm sàng tiêu chuẩn được thực hiện trước và sau phẫu thuật. Cảm giác tê hoặc khó chịu trong phạm vi phân phối C-2 được ghi lại khi tái khám. Tình trạng liền xương được đánh giá bằng cách sử dụng thang điểm liền xương Lenke.

Trong tất cả 44 bệnh nhân, mức mất máu trung bình là 200 ml (khoảng từ 100-350 ml) và thời gian phẫu thuật trung bình là 129 phút (khoảng từ 87-240 phút). Không có biến chứng nào xảy ra trong phẫu thuật, và không có bệnh nhân nào báo cáo khởi phát mới hoặc nặng thêm cơn đau thần kinh C-2 sau phẫu thuật. Kết quả đối với 30 bệnh nhân đã có thời gian theo dõi tối thiểu là 13 tháng (khoảng từ 13–72 tháng) đã được đánh giá. Sau trung bình 36 tháng theo dõi, giá trị Nurick và thang điểm đánh giá đau đã giảm từ 3.7 xuống 1.0 (p < 0.001) và từ 9.4 xuống 0.6 (p < 0.001) tương ứng. Điểm chỉ số khuyết tật cổ sau phẫu thuật trung bình là 7.3%. Tỷ lệ liền xương là 97% và tỷ lệ hài lòng của bệnh nhân là 93%. Tất cả 24 bệnh nhân có đau thần kinh chẩm trước phẫu thuật báo cáo đã giảm đau. Mười bảy bệnh nhân chỉ nhận thấy tê trong phạm vi C-2 trong quá trình kiểm tra tại phòng khám, và 2 bệnh nhân báo cáo tê C-2 nhưng không ảnh hưởng đến chức năng hàng ngày của họ.

Trong chuỗi đoạn nối tầng C1–2 bằng dụng cụ trong những bệnh nhân cao tuổi này, đã đạt được tỷ lệ liền xương xuất sắc và sự hài lòng của bệnh nhân không bị ảnh hưởng xấu bởi việc cắt bỏ thần kinh C-2. Theo kinh nghiệm của tác giả, việc cắt bỏ thần kinh C-2 cải thiện khả năng phô bày phẫu thuật của khớp C1–2, do đó hỗ trợ việc cầm máu, đặt dụng cụ và cắt mài không gian khớp để nối xương. Đáng chú ý, với việc cắt bỏ thần kinh C-2 trong loạt bệnh nhân hiện tại, không có trường hợp nào bị khởi phát sau phẫu thuật thần kinh C-2, trái ngược với số lượng báo cáo ngày càng tăng trong tài liệu cho thấy đau thần kinh C-2 khởi phát mới mà không có cắt bỏ thần kinh C-2. Ngược lại, 80% bệnh nhân trong chuỗi bệnh nhân hiện tại có đau thần kinh chẩm tiền phẫu và trong tất cả những bệnh nhân này, đau thần kinh này đã được giảm bớt sau phẫu thuật dụng cụ nối tầng C1–2 với cắt bỏ thần kinh C-2.

Limited tools exist to stratify perioperative risk in patients undergoing spinal procedures. The modified frailty index (mFI) based on the Canadian Study of Health and Aging Frailty Index (CSHA-FI), constructed from standard demographic variables, has been applied to various other surgical populations for risk stratification. The authors hypothesized that it would be predictive of postoperative morbidity and mortality in patients undergoing spine surgery.

The 2006–2010 National Surgical Quality Improvement Program (NSQIP) data set was accessed for patients undergoing spine surgeries based on Current Procedural Terminology (CPT) codes. Sixteen preoperative clinical NSQIP variables were matched to 11 CSHA-FI variables (changes in daily activities, gastrointestinal problems, respiratory problems, clouding or delirium, hypertension, coronary artery and peripheral vascular disease, congestive heart failure, and so on). The outcomes assessed were 30-day occurrences of adverse events. These were then summarized in groups: any infection, wound-related complication, Clavien IV complications (life-threatening, requiring ICU admission), and mortality.

A total of 18,294 patients were identified. In 8.1% of patients with an mFI of 0 there was at least one morbid complication, compared with 24.3% of patients with an mFI of ≥ 0.27 (p < 0.001). An mFI of 0 was associated with a mortality rate of 0.1%, compared with 2.3% for an mFI of ≥ 0.27 (p < 0.001). Patients with an mFI of 0 had a 1.7% rate of surgical site infections and a 0.8% rate of Clavien IV complications, whereas patients with an mFI of ≥ 0.27 had rates of 4.1% and 7.1% for surgical site infections and Clavien IV complications, respectively (p < 0.001 for both). Multivariate analysis showed that the preoperative mFI and American Society of Anesthesiologists classification of ≥ III had a significantly increased risk of leading to Clavien IV complications and death.

A higher mFI was associated with a higher risk of postoperative morbidity and mortality, providing an additional tool to improve perioperative risk stratification.

This is a retrospective review of 10,242 adults with degenerative spondylolisthesis (DS) and isthmic spondylolisthesis (IS) from the morbidity and mortality (M&M) index of the Scoliosis Research Society (SRS). This database was reviewed to assess complication incidence, and to identify factors that were associated with increased complication rates.

The SRS M&M database was queried to identify cases of DS and IS treated between 2004 and 2007. Complications were identified and analyzed based on age, surgical approach, spondylolisthesis type/grade, and history of previous surgery. Age was stratified into 2 categories: > 65 years and ≤ 65 years. Surgical approach was stratified into the following categories: decompression without fusion, anterior, anterior/posterior, posterior without instrumentation, posterior with instrumentation, and interbody fusion. Spondylolisthesis grades were divided into low-grade (Meyerding I and II) versus high-grade (Meyerding III, IV, and V) groups. Both univariate and multivariate analyses were performed.

In the 10,242 cases of DS and IS reported, there were 945 complications (9.2%) in 813 patients (7.9%). The most common complications were dural tears, wound infections, implant complications, and neurological complications (range 0.7%–2.1%). The mortality rate was 0.1%. Diagnosis of DS had a significantly higher complication rate (8.5%) when compared with IS (6.6%; p = 0.002). High-grade spondylolisthesis correlated strongly with a higher complication rate (22.9% vs 8.3%, p < 0.0001). Age > 65 years was associated with a significantly higher complication rate (p = 0.02). History of previous surgery and surgical approach were not significantly associated with higher complication rates. On multivariate analysis, only the grade of spondylolisthesis (low vs high) was in the final best-fit model of factors associated with the occurrence of complications (p < 0.0001).

The rate of total complications for treatment of DS and IS in this series was 9.2%. The total percentage of patients with complications was 7.9%. On univariate analysis, the complication rate was significantly higher in patients with high-grade spondylolisthesis, a diagnosis of DS, and in older patients. Surgical approach and history of previous surgery were not significantly correlated with increased complication rates. On multivariate analysis, only the grade of spondylolisthesis was significantly associated with the occurrence of complications.

Elderly patients in poor general health frequently suffer vertebral body (VB) fractures due to osteoporosis or vertebral metastatic lesions. Kyphoplasty and vertebroplasty have become the standard treatment for these types of fractures. In certain conditions that cause local kyphosis, such as spinal cord compression due to a metastatic epidural tumor or the shortening of the spinal canal secondary to vertebral compression, the surgical treatment should provide decompression and stabilization during a short intervention. In this study the authors evaluated a surgical technique that frequently combines a same-session surgical decompression, such as a laminectomy, and posterior instrumentation-assisted stabilization during the same open intervention in which the VB is stabilized by kyphoplasty.

During an 18-month period, the authors treated 18 patients with VB fractures according to this protocol: 14 patients with vertebral metastatic lesions and four with osteoporosis. The patients' mean age was 60 years. All suffered severe pain preoperatively (mean visual analog scale [VAS] score of 7). Fourteen of the 18 patients suffered a neurological deficit. Twenty-three vertebral levels were treated; in 15 patients it was necessary to place posterior instrumentation. The mean duration of the intervention was 90 minutes.

Pain in all patients improved 3 days after the intervention, and the mean VAS score decreased to 2. Patients with a neurological dysfunction improved. The mean quantity of injected cement for the kyphoplasty procedure was 7 ml. The mean duration of hospitalization was 7 days. Neuroimaging revealed cement leaks in two cases: one into the disc interspace and one anteriorly into the fractured part of the vertebra. After the intervention, most patients with metastatic lesions underwent radiotherapy. No procedure-related complications occurred.

This procedure allows decompression of the spinal cord, consolidation of the VB and thus a stabilization of the vertebral column, and may provide an alternative treatment to invasive VB excision in patients in poor general health.

The cause of irreducibility in irreducible atlantoaxial dislocation (AAD) appears to be the orientation of the C1–2 facets. The current management strategies for irreducible AAD are directed at removing the cause of irreducibility followed by fusion, rather than transoral decompression and posterior fusion. The technique described in this paper addresses C1–2 facet mobilization by facetectomies to aid intraoperative manipulation.

Using this technique, reduction was achieved in 19 patients with congenital irreducible AAD treated between January 2011 and December 2013. The C1–2 joints were studied preoperatively, and particular attention was paid to the facet orientation. Intraoperatively, oblique C1–2 joints were opened widely, and extensive drilling of the facets was performed to make them close to flat and parallel to each other, converting an irreducible AAD to a reducible one. Anomalous vertebral arteries (VAs) were addressed appropriately. Further reduction was then achieved after vertical distraction and joint manipulation.

Adequate facet drilling was achieved in all but 2 patients, due to VA injury in 1 patient and an acute sagittal angle operated on 2 years previously in the other patient. Complete reduction could be achieved in 17 patients and partial in the remaining 2. All patients showed clinical improvement. Two patients showed partial redislocation due to graft subsidence. The fusion rates were excellent.

Comprehensive drilling of the C1–2 facets appears to be a logical and effective technique for achieving direct posterior reduction in irreducible AAD. The extensive drilling makes large surfaces raw, increasing fusion rates.

Stabilization of the craniovertebral junction (CVJ) by using lateral masses requires extensive dissection. The vertebral artery (VA) is commonly anomalous in patients with congenital CVJ anomaly. Such a vessel is likely to be injured during dissection or screw placement. In this study the authors discuss the importance of preoperative evaluation and certain intraoperative steps that reduce the chances of injury to such vessels.

A 3D CT angiogram was obtained in 15 consecutive patients undergoing surgery for congenital atlantoaxial dislocation. The course of the VA and its relationship to the C1–2 facets was studied in these patients. The anomalous VA was exposed intraoperatively, facet surfaces were drilled in all, and the screws were placed according to the disposition of the vessel.

A skeletal anomaly was found in all 10 patients who had an anomalous VA. Four types of variations were noted: 1) the first intersegmental artery in 5 patients (bilateral in 1); 2) fenestration of VA in 1 patient; 3) anomalous posterior inferior cerebellar artery crossing the C1–2 joint in 1 patient; and 4) medial loop of VA in 5 patients. The anomalous vessel was dissected and the facet surfaces were drilled in all. The C-1 lateral mass screw was placed under vision, taking care not to compromise the anomalous vessel, although occipital screws or sublaminar wires were used in the initial cases. A medial loop of the VA necessitated placement of transpedicular or C-2 lateral mass screws instead of pars interarticularis screws. The anomalous vessel was injured in none.

Preoperative 3D CT angiography is a highly useful method of imaging the artery in patients with CVJ anomaly. It helps in identifying the anomalous VA or its branch and its relationship to the C1–2 facets. The normal side should be surgically treated and distracted first because this helps in opening the abnormal side, aiding in dissection. In the posterior approach the C-2 nerve root is always encountered before the anomalous vessel. The defined vascular anatomy helps in choosing the type of screw. The vessel should be mobilized so as to aid the drilling of facets and the placement of screws and spacers under vision, avoiding its injury (direct or indirect) or compression. With these steps, C1–2 (short segment) rigid fusion can be achieved despite the presence of anomalous VA.