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anterior_cervical_discectomy_and_fusion

Anterior cervical discectomy and fusion (ACDF)

Anterior cervical discectomy and fusion (ACDF) and cervical laminoplasty (LP) are the most commonly performed procedures for degenerative cervical spondylosis.

Without and with cervical plating (ACDF+CP) are accepted surgical techniques for the treatment of degenerative cervical disc disorder.

It is used to treat cervical degenerative disease that induces an osteophyte or a disc herniation that then causes radiculopathy or myelopathy 1) 2)

This spine surgery is one of the most prevalent performed, and the frequency of its performance is rapidly increasing as the aging population grows. Although ASCs offer significant cost advantages over hospital-based surgical centers, concern over the safety of outpatient ACDF has slowed its adoption.

Interbody fusion is performed with bone grafts or interbody cages, and may be supplemented with anterior cervical plates.

History

The earliest descriptions of the technique have always been attributed to Cloward, Smith, and Robinson. However, in the French literature, this procedure was also described by others during the exact same time period (in the 1950s). At a meeting in Paris in 1955, Belgians Albert Dereymaeker and Joseph Cyriel Mulier, a neurosurgeon and an orthopedic surgeon, respectively, described the technique that involved an anterior cervical discectomy and the placement of an iliac crest graft in the intervertebral disc space. In 1956, a summary of their oral presentation was published, and a subsequent paper-an illustrated description of the technique and the details of a larger case series with a 3.5-year follow-up period-followed in 1958. The list of authors who first described ACDF should be completed by adding Dereymaeker's and Mulier's names. They made an important contribution to the practice of spinal surgery that was not generally known because they published in French 3).

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Epidemiology

From 1999 to 2008, the annual number of cervical discectomies with subsequent fusion for degenerative disc diseases in the USA increased by 67% 4).

Indications

Once conservative treatment for cervical radiculopathy, cervical spondylotic myelopathy, or both, has failed, surgical intervention is indicated 5).

It has been shown that ACDF induces biomechanical changes leading to modifications of intradiscal pressure pressure recordings in the cervical spine 6) 7) 8) and to increased stress and motion of vertebral segments adjacent to the fused ones.

see Anterior cervical discectomy and fusion for cervical spondylotic myelopathy.

Technique

The operation is usually straightforward but has multiple pitfalls and nuances 9)

see PDF article of Sonntag VK, Han PP, Vishteh AG. Anterior cervical discectomy. Neurosurgery. 2001 Oct;49(4):909-12. PubMed PMID: 11564253.

In the operating room, the patient must not be hyperextended during intubation.

Somatosensory evoked potentials are routinely monitored.

The patient is placed supine with the neck slightly hyperextended. The head is not turned.

Superficial landmarks serve as the reference points to determine the level of the skin incision, but intraoperative radiographs or fluoroscopic studies are obtained to verify the level.

The cervical spine is approached from the right side unless the patient has undergone a prior approach from the left side. If so, the original incision line is used. If a patient has subclinical vocal cord palsy on the side of the incision, proceeding with an incision on the opposite side is risky. The potential for recurrent laryngeal nerve palsy is highest on the right side, although the risk has not been documented in recent reports. The thoracic duct, however, can be injured when the approach is from the left side.

Closure

After copious irrigation, the wound is closed. It is inspected once more by placing two self-retaining Cloward retractors in the wound, keeping one self-retaining retractor deep in the wound. The walls of the wound are checked for any bleeding, which is then controlled, and the opposite retractor is removed slowly. The same maneuver is performed on the other side. The platysma layer is closed with interrupted 3-0 Vicryl suture (Ethicon, Inc., Somerville, NJ), and the skin is closed with a running subcuticular 4-0 Vicryl suture. The suture line is reinforced with Steri-Strips (3M Healthcare, St. Paul, MN) or Dermabond (Closure Medical Corp., Raleigh, NC).

Video

Interbody spacer

For interbody fusions, autograft was the gold standard for decades; however, limited availability and donor site morbidities have led to a constant search for new materials. Clinically, it has been shown that calcium phosphate ceramics, including hydroxyapatite (HA) and tricalcium phosphate (TCP), are effective as osteoconductive materials and bone grafts.

Many options for interbody spacer and graft biologic exist for multilevel anterior cervical discectomy and fusion (ACDF).

Cornerstone HSR, Medtronic Sofamor Danek….

see Cervical cage.

Follow up

Following ACDF, imaging modalities such as standard radiography and computed tomography (CT) are used to assess the fusion, instrumentation failure, and postoperative change such as adjacent segment disease

No standard algorithm for postoperative imaging following ACDF has been defined formally, and the frequency and type of imaging obtained is left to the surgeon's discretion. Due to their relatively low cost and ease of administration, 10).

Due to their relatively low cost and ease of administration, standard radiographs are often ordered for all patients following ACDF to assess fusion status.

However, the use of such “routine” postoperative radiographs has been found to be unwarranted in asymptomatic patients 11) 12) 13).

The ACDF procedure itself can induce regional slope change (C5-s and C7-s) directly at the surgical level and can also influence upper cervical slope change (C1-s and C2s) indirectly. Then the change in the upper cervical spine can induce a change in the sagittal vertical axis (St-SVA) and spino-cranial angle (SCA) 14).

Flexion-extension radiographs

Flexion-extension radiographs are obtained 6 weeks after the operation in patients with a fusion construct. If evidence of fusion is present and there are no signs of pseudarthrosis, patients are started on exercise therapy at that time. Patients who do not undergo a fusion procedure can start exercise 2 to 3 weeks after surgery.

CT

CT is a more sensitive alternative to plain radiography when assessing fusion because of its ability to detail bridging trabecular bone 15).

CT scans following ACDF are not routinely ordered. A CT results in alteration of the treatment in 60% of patients with an abnormal MRI and/or radiograph and persistent symptoms. In contrast, if the patient only has persistent symptoms, only 39% of them will go onto further intervention, suggesting that CT has a limited utility in this population. The probability of detecting abnormal findings on CT subsequent to ACDF is significantly greater when the patient presents with persistent symptoms or abnormal preliminary imaging. Alterations in the treatment course based on abnormal postoperative CT are dependent on postoperative symptoms. Those patients who undergo CT without indication (i.e., without preimaging symptoms or abnormal imaging) are significantly more likely to have negative findings on CT, and even with abnormal CT findings, they are less likely to have an alteration in the treatment course. As such, postoperative CTs following ACDF should be limited to patients who have persistent debilitating symptoms or those with abnormal imaging. This practice will avoid unnecessary cost and patient exposure to ionizing radiation 16).

For patients who undergo a fusion procedure, anterior and lateral radiographs are obtained in the recovery room to verify the position of the graft, the plate, and the screws. Patients without an internal fixation device wear a rigid collar for 4 to 6 weeks. In patients who receive internal fixation and in those who undergo no fusion, external orthosis is not applied routinely, except to control pain. Patients are discharged the day after surgery. A problem with swallowing is the usual reason why patients are kept longer in the hospital. Within 7 to 10 days of discharge, patients are seen in the office for a “wound check.”

Complications

Outcome

Case series

1)
Cloward RB: The anterior approach for removal of ruptured cervical disks. J Neurosurg 15:602–617, 1958.
2)
Robinson RA, Smith GW: Anterolateral cervical disc removal and interbody fusion for cervical disc syndrome. Bull John Hopkins Hosp 96:223–224, 1955.
3)
Bartels RHMA, Goffin J. Albert Dereymaeker and Joseph Cyriel Mulier's description of anterior cervical discectomy with fusion in 1955. J Neurosurg Spine. 2018 Jan 12:1-6. doi: 10.3171/2017.7.SPINE17182. [Epub ahead of print] PubMed PMID: 29327972.
4)
McGuire KJ, Harrast J, Herkowitz H, Weinstein JN. Geographic variation in the surgical treatment of degenerative cervical disc disease: American board of orthopedic surgery quality improvement initiative; Part II candidates. Spine (Phila Pa 1976) 2012;37:57–66. doi: 10.1097/BRS.0b013e318212bb61.
5)
Sonntag VK, Han PP, Vishteh AG. Anterior cervical discectomy. Neurosurgery. 2001 Oct;49(4):909-12. PubMed PMID: 11564253.
6)
POSPIECH J, STOLKE D, WILKE HJ, CLAES LE. Intradiscal pressure recordings in the cervical spine. J Neu- rosurg 1999; 44: 379-385.
7)
WEINHOFFER SL, GUYER RD, HERBERT M, GRIFFITH SL. Intradiscal pressure measurements above an in- strumented fusion. A cadaveric study. Spine 1995; 20: 526-531.
8)
WIGFIELD CC, SKRZYPIEC D, JACKOWSKI A, ADAMS MA. Internal stress distribution in cervical interverte- bral discs: the influence of an artificial cervical joint and simulated anterior interbody fusion. J Spinal Disord Tech 2003; 16: 441-449.
9)
Golfinos JG, Dickman CA, Zabramski JM, Sonntag VKH, Spetzler RF: Repair of vertebral artery injury during anterior cervical decompression. Spine 19:2552–2556, 1994.
10)
Herzog R J, Marcotte P J. Assessment of spinal fusion. Critical evaluation of imaging techniques. Spine (Phila Pa 1976) 1996;21(9):1114–1118.
11)
Shau D N, Bible J E, Samade R. et al. Utility of postoperative radiographs for cervical spine fusion: a comprehensive evaluation of operative technique, surgical indication, and duration since surgery. Spine (Phila Pa 1976) 2012;37(24):1994–2000.
12)
Bartels R HMA, Beems T, Schutte P J, Verbeek A L. The rationale of postoperative radiographs after cervical anterior discectomy with stand-alone cage for radicular pain. J Neurosurg Spine. 2010;12(3):275–279.
13)
Ugokwe K T, Kalfas I H, Mroz T E, Steinmetz M P. A review of the utility of obtaining repeated postoperative radiographs following single-level anterior cervical decompression, fusion, and plate placement. J Neurosurg Spine. 2008;9(2):175–179.
14)
Lee HJ, Choi DY, Shin MH, Kim JT, Hong JT. Sequential alignment change of the cervical spine after anterior cervical discectomy and fusion in the lower cervical spine. Eur Spine J. 2016 Jan 28. [Epub ahead of print] PubMed PMID: 26821140.
15)
Selby M D, Clark S R, Hall D J, Freeman B J. Radiologic assessment of spinal fusion. J Am Acad Orthop Surg. 2012;20(11):694–703.
16)
Derakhshan A, Lubelski D, Steinmetz MP, Benzel EC, Mroz TE. Utility of Computed Tomography following Anterior Cervical Diskectomy and Fusion. Global Spine J. 2015 Oct;5(5):411-6. doi: 10.1055/s-0035-1554773. Epub 2015 Jun 5. PubMed PMID: 26430596; PubMed Central PMCID: PMC4577315.
anterior_cervical_discectomy_and_fusion.txt · Last modified: 2018/09/11 08:39 by administrador