Janjua M Burhan, Zhou Peter L, Greenfield Jeffrey P, Baaj Ali A, Frempong-Boadu Anthony
Neurosurgery/Spine Surgery, New York University Langone Medical Center.
Hospital for Joint Diseases, New York University Langone Medical Center.
Cureus. 2017 Mar 3;9(3):e1074. doi: 10.7759/cureus.1074.
Posterior C1-C2 fusion is a highly successful treatment for atlantoaxial instability and other pathologies of the cervical spine, with fusion rates approaching 95%-100%. However, poor visualization of the lateral masses of C1 secondary to the course of the C2 nerve root along with blood loss from the venous plexus and compression of the C2 nerve from lateral mass screws are technical obstacles that can arise during surgery. Thus, sacrifice of the C2 nerve root has long since been debated in fusions involving the C1 and C2 vertebral bodies.
Cadaveric dissections on four adult specimens were performed. Both intradural and extradural courses of C2 were studied in detail. The tentative site of C2 nerve root compression during placement of C1 lateral mass screws was studied in detail. Both the indication as well as the ease of C2 neurectomy were studied in relation to postoperative compression and entrapment.
Four-six dorsal rootlets of C2 nerve were observed while studying the intradural course. The extradural course was studied with respect to the lateral mass of C1. The greater occipital nerve (GON) course was fairly consistent in all specimens. Transection of C2 around its ganglion would allow for proper C1 lateral mass screw placement as the course of C2 nerve interferes with proper placement of instrumentation.
C2 nerve root transection is associated with occipital numbness but this often has no effect on health-related quality of life (HRQOL). The C2 nerve root preservation is often associated with entrapment neuropathy or occipital neuralgia, which greatly affects HRQOL. The C2 nerve root transection helps in better visualization, aids in optimal placement of C1 lateral mass screws, minimizes estimated blood loss and improves surgical outcome with successful fusion.
C1-C2后路融合术是治疗寰枢椎不稳及其他颈椎疾病的一种非常成功的方法，融合率接近95%-100%。然而，由于C2神经根走行导致C1侧块视野不佳，以及静脉丛出血和侧块螺钉对C2神经的压迫，是手术中可能出现的技术障碍。因此，在涉及C1和C2椎体的融合术中，C2神经根的牺牲一直存在争议。
对四个成年标本进行尸体解剖。详细研究了C2的硬膜内和硬膜外走行。详细研究了C1侧块螺钉置入过程中C2神经根受压的暂定部位。研究了C2神经切除术的指征以及难易程度与术后压迫和卡压的关系。
在研究硬膜内走行时观察到C2神经的四到六个背根丝。针对C1侧块研究了硬膜外走行。在所有标本中，枕大神经（GON）走行相当一致。由于C2神经走行会干扰器械的正确置入，在其神经节周围横断C2可使C1侧块螺钉正确置入。
C2神经根横断与枕部麻木有关，但这通常对健康相关生活质量（HRQOL）没有影响。保留C2神经根常与卡压性神经病变或枕神经痛有关，这会极大地影响HRQOL。C2神经根横断有助于更好地显露，有助于C1侧块螺钉的最佳置入，减少估计失血量，并通过成功融合改善手术效果。
