Posterior cervical decompression

Posterior cervical decompression

Not typically used for a herniated cervical disc, more common for cervical spinal stenosisOPLL

● without posterior fusion

● with lateral mass fusion

b) keyhole laminotomy: sometimes permits removal of disc fragment

Usually reserved for the following conditions:

multiple cervical discs or osteophytes (anterior cervical discectomy (ACD) is usually used to treat only 2, or possibly 3, levels without) with myelopathy.

where the anterior pathology is superimposed on cervical stenosis, and the latter is more diffuse and/or more significant

in professional speakers or singers where the 4% risk of permanent voice change due to recurrent laryngeal nerve injury with ACD may be unacceptable.

Laminectomy and facetectomy are commonly used surgical procedures for decompressing cervical spinal stenosis. Resection of the posterior structures causes instability and affects the internal stresses of the cervical spinal components. However, the influence of these surgical procedures on the biomechanical responses of the cervical spine has not been studied.

A nonlinear finite element model of the intact C2-C7 was constructed and validated. Ten surgically altered models were created from the intact model and were tested under physiologic loading. Because of the inclusion of five motion segments, it was possible to determine the intersegmental responses and internal cortical shell and disc stresses in the adjacent altered and unaltered spinal components.

Under combined flexion and extension, intersegmental motions at C4-C5 and C5-C6 increased significantly after C5 laminectomy. Subsequent facetectomy performed at C5 and C6 on the laminectomized model only affected the responses at the C5-C6 segment. Overall, slight intersegmental responses of up to 5% were observed at the adjacent levels of C3-C4 and C6-C7. Laminectomy did not cause any significant increase in the intersegmental motions under lateral bending and axial rotation. Extending the surgical procedures to unilateral and bilateral facetectomy only increased the intersegmental motions slightly. Similar increases in the intervertebral disc and the cortical shell stresses were observed. These findings may partially explain the clinical observations of enhanced osteophytes formation.

This study provides a better understanding of the surgically altered cervical spinal biomechanics and may help formulate treatment strategies such as spinal implants 1).

Its a posterior cervical spine surgery, for cervical spinal stenosis. The spine surgeon removes a small section of the lamina to relieve compression on the nerve. The remaining spinal bones are connected back together with titanium metal rods and screws.

The skin incision is in the midline of the back of the neck and is about 3 to 4 inches long. The paraspinal muscles are then elevated from multiple levels. Removal of the lamina. A high-speed burr can be used to make a trough in the lamina on both sides right before it joins the facet joint. The lamina with the spinous process can then be removed as one piece (like a lobster tail). Removal of the lamina and spinous process allows the spinal cord to float backwards and gives it more room.

Cervical laminectomy resulted in the greatest increase in global cervical ROM. Resection of the intraspinous and supraspinous ligaments [ISLs).ISLs at C2-3 and C7-T1 increased segmental ROM at these specific levels to a similar extent that laminectomy increased ROM at each cervical level. This segmental ROM may contribute to pain or postprocedural deformity and highlights the importance of the ISLs at the terminal ends of the cervical open door laminoplasty (ODL) 2).

Cervical laminectomy complications.

Prone, some use pin head holder

a) C-arm

b) high speed drill

  1. implants: cervical lateral mass screws and rods if fusion is being done

4. neuromonitoring: some surgeons used SSEP/MEP: Use of intra-op EP monitoring during a routine surgery for CSM or cervical radiculopathy is not recommended as an indication to alter the surgical plan or administer steroids since this paradigm has not been observed to reduce the incidence of neurologic injury (Level D Class III).

5. consent (in lay terms for the patient—not all-inclusive):

a) procedure: surgery through the back of the neck to remove the bone over the compressed spinal cord and nerves and possibly to place screws and rods to fuse the boned together

b) alternatives: nonsurgical management, surgery from the front of the neck, posterior surgery without fusion, laminoplasty

c) complications: nerve root weakness (C5 nerve root is the most common), may not relieve symptoms, further surgery may be needed, possible seizures with MEPs. If fusion is not done, there is a risk of progressive bone slippage, which would require further surgery.

Posterior cervical decompression and fusion.

Posterior fossa decompression for Chiari type 1 deformity.


Hong-Wan N, Ee-Chon T, Qing-Hang Z. Biomechanical effects of C2-C7 intersegmental stability due to laminectomy with unilateral and bilateral facetectomy. Spine (Phila Pa 1976). 2004 Aug 15;29(16):1737-45; discussion 1746. PubMed PMID: 15303016.

Healy AT, Lubelski D, West JL, Mageswaran P, Colbrunn R, Mroz TE. Biomechanics of open-door laminoplasty with and without preservation of posterior structures. J Neurosurg Spine. 2016 May;24(5):746-51. doi: 10.3171/2015.7.SPINE15229. Epub 2016 Jan 22. PubMed PMID: 26799115.

Anterior cervical discectomy

Anterior cervical discectomy

The most common surgical techniques are cervical discectomy with or without fusing the two adjacent intervertebral bodies. Robinson and Smith 1) 2) 3) 4). introduced the anterior cervical decompression technique without microscope, but with fusion by inserting a bone graft harvested from the iliac crest of the patient.

Hankinson and Wilson 5) improved the procedure with the use of an operating microscope; however, they performed the surgery without leaving a graft behind; the results of both types of surgery were entirely comparable 6) 7) 8).

In time several modifications of these surgical techniques have been made 9) 10) 11).

Surgical decompression for cervical radiculopathy includes:

1.- Anterior cervical discectomy without any prosthesis or fusion: rarely used today.

2.- Anterior cervical discectomy and fusion with interbody fusion: the most common approach.

a.- without anterior cervical plate.

b.- with anterior cervical plate or with zero profile.

3.- with artificial disc: see Cervical disc arthroplasty

4.- Percutaneous

a.- Anterior percutaneous cervical disc chemonucleolysis.

Tissue trauma is significantly reduced with laser and endoscopic surgery techniques. Anterior cervical laser discectomy and Anterior percutaneous endoscopic cervical discectomy are both suitable for the specific indication of soft, symptomatic contained cervical disc herniations. A prospective cohort study indicates that Anterior cervical laser discectomy and Anterior percutaneous endoscopic cervical discectomy are options for cervical decompression surgery when medical comorbidities or preferences by patients and surgeons dictate more minimally invasive strategies 12).

see Anterior cervical discectomy technique

see Anterior cervical discectomy complications.

see Anterior cervical discectomy outcome.

see Anterior cervical discectomy case series.


Aronson N, Filtzer Dl, Bugan M. Anterior cervical fusion by the Smith–Robinson approach. J Neurosurg. 1968;29:397–404.

Robinson RA, Smith GW. Anterolateral cervical disc removal and interbody fusion for cervical disc syndrome. Bull John Hopkins Hosp. 1955;96(Suppl):223–224.

Robinson RA. Anterior and posterior cervical spine fusions. Clin Orthop Relat Res. 1964 Jul-Aug;35:34-62. PubMed PMID: 5889170.

SMITH GW, ROBINSON RA. The treatment of certain cervical-spine disorders by anterior removal of the intervertebral disc and interbody fusion. J Bone Joint Surg Am. 1958 Jun;40-A(3):607-24. PubMed PMID: 13539086.

Hankinson HL, Wilson CB. Use of the operating microscope in anterior cervical discectomy without fusion. J Neurosurg. 1975 Oct;43(4):452-6. PubMed PMID: 1159482.

Abd-Alrahman N, Dokmak AS, Abou-Madawi A. Anterior cervical discectomy (ACD) versus anterior cervical fusion (ACF), clinical and radiological outcome study. Acta Neurochir (Wien). 1999;141(10):1089-92. PubMed PMID: 10550654.

Dowd GC, Wirth FP. Anterior cervical discectomy: is fusion necessary? J Neurosurg. 1999 Jan;90(1 Suppl):8-12. PubMed PMID: 10413119.

Jacobs WC, Anderson PG, Limbeek J, Willems PC, Pavlov P. Single or double-level anterior interbody fusion techniques for cervical degenerative disc disease. Cochrane Database Syst Rev. 2004 Oct 18;(4):CD004958. Review. Update in: Cochrane Database Syst Rev. 2011;(1):CD004958. PubMed PMID: 15495130.

Baskin DS, Ryan P, Sonntag V, Westmark R, Widmayer MA. A prospective, randomized, controlled cervical fusion study using recombinant human bone morphogenetic protein-2 with the CORNERSTONE-SR allograft ring and the ATLANTIS anterior cervical plate. Spine (Phila Pa 1976). 2003 Jun 15;28(12):1219-24; discussion 1225. PubMed PMID: 12811263.

CLOWARD RB. The anterior approach for removal of ruptured cervical disks. J Neurosurg. 1958 Nov;15(6):602-17. PubMed PMID: 13599052.

Madawi AA, Powell M, Crockard HA. Biocompatible osteoconductive polymer versus iliac graft. A prospective comparative study for the evaluation of fusion pattern after anterior cervical discectomy. Spine (Phila Pa 1976). 1996 Sep 15;21(18):2123-9; discussion 2129-30. PubMed PMID: 8893437.

Hellinger S, Knight M, Telfeian AE, Lewandrowski KU. Patient selection criteria for percutaneous anterior cervical laser versus endoscopic discectomy. Lasers Surg Med. 2022 Jan 6. doi: 10.1002/lsm.23514. Epub ahead of print. PMID: 34989414.

Cervical Cage Subsidence

Cervical Cage Subsidence

Cage subsidence was defined as the sum subsidence of the superior and inferior part of the cage into the vertebral body. Mild and major cage subsidence was defined as ≤2 mm and >2 mm, respectively. The extent of cage subsidence was greater after ACDF with cage alone. Cage subsidence occurred more often when the end plate was removed. Additional anterior plate fixation is recommended when the end plate is removed 1).

Subsidence in ACDF with cages occurs in 21% of patients. The risk for subsidence seems lower using PEEK or titanium cages or adding screws 2).

Zero profile anchored spacer (ROI-C) use resulted in a higher subsidence rate than conventional cage and plate construct (CPC) use in multi-segment ACDF procedures. The male sex, the use of ROI-C, operation in multiple segments, and over-distraction were the most significant factors associated with an increase in the risk of cage subsidence 3).

The greater the cage height, the greater the risk of cage subsidence in ACDF. Polyetheretherketone cages are superior to titanium cages for the maintenance of intervertebral height in cases where cage height is >5.5 mm 4)

Subsidence irrespective of the measurement technique or definition does not appear to have an impact on successful fusion and/or clinical outcomes. A validated definition and standard measurement technique for subsidence is needed to determine the actual incidence of subsidence and its impact on radiographic and clinical outcomes 5).

PEEK cages showed a high rate of secondary subsidence (32%) 6).

Titanium Wing cage-augmented ACDF was associated with comparatively good long-term results. Subsidence was present but did not cause clinical complications. Furthermore, radiological studies demonstrated that the physiological alignment of the cervical spine was preserved and a solid bone arthrodesis was present at 2 years after surgery 7).

There is evidence documenting relatively frequent complications in stand-alone cage assisted ACDF, such as cage subsidence and cervical kyphosis 8).

Subsidence irrespective of the measurement technique or definition does not appear to have an impact on successful fusion and/or clinical outcomes. A validated definition and standard measurement technique for subsidence is needed to determine the actual incidence of subsidence and its impact on radiographic and clinical outcomes 9).

Findings suggest that the value of ratio of anterior endplate more than 1.18, alignment of titanium mesh cage (TMC) and poor bone mineral density are the risk factors for subsidence. TMC subsidence does not negatively affect the clinical outcomes after operation. Avoiding over expansion of intervertebral height, optimizing placing of TMC and initiation of anti-osteoporosis treatments 6 months prior to surgery might help surgeons to reduce subsidence after ACCF 10).

Lee et al. from Yangsan retrospectively reviewed the medical records of 40 patients who underwent stand-alone single-level ACDF using a polyetheretherketone (PEEKcage between January 2012 and December 2018. The study population comprised 19 male and 21 female patients aged 24-70 years. The minimum follow-up period was 1 year. Twenty-seven patients had preoperative bone mineral density (BMD) data on dual-energy X-ray absorptiometry. Clinical parameters included sex, age, body mass indexsmoking history, and prior medical history. Radiologic parameters included the C2-7 cobb angle, segmental angle, sagittal vertical axis, disc height, and total intervertebral height (TIH) at the preoperative and postoperative periods. Cage decrement was defined as the reduction in TIH at the 6-month follow-up compared to preoperative TIH. To evaluate the bone quality, Hounsfield unit (HU) value was calculated in the axial and sagittal images of conventional computed tomography.

Lumbar BMD values and cervical HU values were significantly correlated (r=0.733, p<0.001). They divided the patients into two groups based on cage decrement, and 47.5% of the total patients were regarded as cage decrement. There were statistically significant differences in the parameters of measuring the HU value of the vertebra and intraoperative distraction between the two groups. Using these identified factors, we performed a receiver operating characteristic (ROC) curve analysis. Based on the ROC curve, the cut-off point was 530 at the HU value of the upper cortical and cancellous vertebrae (p=0.014; area under the curve [AUC], 0.727; sensitivity, 94.7%; specificity, 42.9%) and 22.41 at intraoperative distraction (p=0.017; AUC, 0.722; sensitivity, 85.7%; specificity, 57.9%). Using this value, they converted these parameters into a bifurcated variable and assessed the multinomial regression analysis to evaluate the risk factors for cage decrement in ACDF. Intraoperative distraction and HU value of the upper vertebral body were independent factors of postoperative subsidence.

Insufficient intraoperative distraction and low Hounsfield unit (HU) value showed a strong relationship with postoperative intervertebral height reduction following single stand-alone PEEK cage ACDF 11).

Mende et al. performed a retrospective analysis of ACDF patients from 2004 to 2010. Numeric analog scale (NAS) score pre-op and post-op, Oswestry Disability Index (ODI) on x-rays, endplate (EP) and cage dimensions, implant position, lordotic/kyphotic subsidence patterns (>5°), and cervical alignment were recorded. Subsidence was defined as height loss >40%. Patients were grouped into single segment (SS), double segment (DS), and plated procedures. We included 214 patients. Prevalence of subsidence was 44.9% overall, 40.9% for SS, and 54.8% for DS. Subsidence presented mostly for dorsal (40.7%) and mid-endplate position (46.3%, p < 0.01); dorsal placement resulted in kyphotic (73.7%) and central placement in balanced implant migration (53.3%, p < 0.01). Larger cages (>65% EP) showed less subsidence (64.6 vs. 35.4%, p < 0.01). There was no impact of subsidence on ODI or alignment. NAS was better for subsided implants in SS (p = 0.06). Cages should be placed at the anterior endplate rim in order to reduce the risk of subsidence. Spacers should be adequately sized for the respective segment measuring at least 65% of the segment dimensions. The cage frame should not rest on the vulnerable central endplate. For multilevel surgery, ventral plating may be beneficial regarding construct stability. The reduction of micro-instability or over-distraction may explain lower NAS for subsided implants 12).

a retrospective observational cohort study to test the hypothesis that radiographic subsidence of cervical cages is not associated with adverse clinical outcomes. 33 cervical segments were treated surgically by ACDF with stand-alone cage in 17 patients (11 female, 6 male), mean age 56 years (33-82 years), and re-examined after eight and twenty-six months (mean) by means of radiology and score assessment (Medical Outcomes Study Short Form (MOS-SF 36), Oswestry Neck Disability Index (ONDI), painDETECT questionnaire and the visual analogue scale (VAS)).

Results: Subsidence was observed in 50.5% of segments (18/33) and 70.6% of patients (12/17). 36.3% of cases of subsidence (12/33) were observed after eight months during mean time of follow-up 1. After 26 months during mean time of follow-up 2, full radiographic fusion was seen in 100%. MOS-SF 36, ONDI and VAS did not show any significant difference between cases with and without subsidence in the two-sample t-test. Only in one type of scoring (painDETECT questionnaire) did a statistically significant difference in t-Test emerge between the two groups (p = 0.03; α = 0.05). However, preoperative painDETECT score differ significantly between patients with subsidence (13.3 falling to 12.6) and patients without subsidence (7.8 dropped to 6.3).

Conclusions: The radiological findings indicated 100% healing after stand-alone treatment with ACDF. Subsidence occurred in 50% of the segments treated. No impact on the clinical results was detected in the medium-term study period 13).


Pinder EM, Sharp DJ. Cage subsidence after anterior cervical discectomy and fusion using a cage alone or combined with anterior plate fixation. J Orthop Surg (Hong Kong). 2016 Apr;24(1):97-100. doi: 10.1177/230949901602400122. PMID: 27122522.

Noordhoek I, Koning MT, Jacobs WCH, Vleggeert-Lankamp CLA. Incidence and clinical relevance of cage subsidence in anterior cervical discectomy and fusion: a systematic review. Acta Neurochir (Wien). 2018 Apr;160(4):873-880. doi: 10.1007/s00701-018-3490-3. Epub 2018 Feb 21. PMID: 29468440; PMCID: PMC5859059.

Jin ZY, Teng Y, Wang HZ, Yang HL, Lu YJ, Gan MF. Comparative Analysis of Cage Subsidence in Anterior Cervical Decompression and Fusion: Zero Profile Anchored Spacer (ROI-C) vs. Conventional Cage and Plate Construct. Front Surg. 2021 Oct 27;8:736680. doi: 10.3389/fsurg.2021.736680. PMID: 34778358; PMCID: PMC8579909.

Igarashi H, Hoshino M, Omori K, Matsuzaki H, Nemoto Y, Tsuruta T, Yamasaki K. Factors Influencing Interbody Cage Subsidence Following Anterior Cervical Discectomy and Fusion. Clin Spine Surg. 2019 Aug;32(7):297-302. doi: 10.1097/BSD.0000000000000843. PMID: 31169615.
5) , 9)

Karikari IO, Jain D, Owens TR, Gottfried O, Hodges TR, Nimjee SM, Bagley CA. Impact of Subsidence on Clinical Outcomes and Radiographic Fusion Rates in Anterior Cervical Discectomy and Fusion: A Systematic Review. J Spinal Disord Tech. 2014 Feb;27(1):1-10. PubMed PMID: 24441059.

König SA, Spetzger U. Distractable titanium cages versus PEEK cages versus iliac crest bone grafts for the replacement of cervical vertebrae. Minim Invasive Ther Allied Technol. 2013 Nov 29. [Epub ahead of print] PubMed PMID: 24289173.

Schmieder K, Wolzik-Grossmann M, Pechlivanis I, Engelhardt M, Scholz M, Harders A. Subsidence of the wing titanium cage after anterior cervical interbody fusion: 2-year follow-up study. J Neurosurg Spine. 2006 Jun;4(6):447-53. PubMed PMID: 16776355.

Cloward RB: The anterior approach for removal of ruptured cervical disks. 1958. J Neurosurg Spine 6:496-511, 2007

Ji C, Yu S, Yan N, Wang J, Hou F, Hou T, Cai W. Risk factors for subsidence of titanium mesh cage following single-level anterior cervical corpectomy and fusion. BMC Musculoskelet Disord. 2020 Jan 14;21(1):32. doi: 10.1186/s12891-019-3036-8. PMID: 31937288; PMCID: PMC6961320.

Lee JS, Son DW, Lee SH, Ki SS, Lee SW, Song GS, Woo JB, Kim YH. The Effect of Hounsfield Unit Value with Conventional Computed Tomography and Intraoperative Distraction on Postoperative Intervertebral Height Reduction in Patients Following Stand-Alone Anterior Cervical Discectomy and Fusion. J Korean Neurosurg Soc. 2021 Dec 29. doi: 10.3340/jkns.2021.0131. Epub ahead of print. PMID: 34963207.

Mende KC, Eicker SO, Weber F. Cage deviation in the subaxial cervical spine in relation to implant position in the sagittal plane. Neurosurg Rev. 2017 Apr 4. doi: 10.1007/s10143-017-0850-z. [Epub ahead of print] PubMed PMID: 28374128.

Zajonz D, Franke AC, von der Höh N, Voelker A, Moche M, Gulow J, Heyde CE. Is the radiographic subsidence of stand-alone cages associated with adverse clinical outcomes after cervical spine fusion? An observational cohort study with 2-year follow-up outcome scoring. Patient Saf Surg. 2014 Nov 7;8(1):43. doi: 10.1186/s13037-014-0043-4. PMID: 25408710; PMCID: PMC4234826.
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