A Sterile-freehand Reduction Technique for Corrective Osteotomy of Fixed Cervical Kyphosis

Sang-Hun Lee, MD; Ki-Tack Kim, MD; Kyung-Soo Suk, MD; Man-Ho Kim, MD; Dae-Hyun Park, MD; Kyu-Jin Kim, MD


Spine. 2012;37(26):2145-2150. 

In This Article

Abstract and Introduction


Study Design. A technical note and a retrospective review of cervical osteotomy using an innovative reduction technique.

Objective. To present the clinical and radiological outcomes and effectiveness of the sterile-freehand reduction technique for cervical osteotomy.

Summary of Backgroud Data. For a successful osteotomy, controlled reduction of deformity after complete release of bony deformity is the most critical step. Conventional "unscrubbed-scrubbed" manual reduction techniques necessitate multiple releases and retightening of the clamp and are inconvenient for the surgeon to control the force and monitor the surgical field closely.

Methods. A total of 7 consecutive patients (5 male and 2 female; mean age, 52.6 yr) who underwent corrective osteotomy of the fixed cervical kyphosis by a single surgeon were enrolled. Radiographically, C2–C7 sagittal and coronal angle, and the chin-brow vertical angle were measured. In the prone position, the entire head and the Gardner-Wells tong were included in the surgical field, and a sterile rope was connected to a weight through a hole made in the surgical drape. After complete release of bony element and fixation of the caudal part of osteotomy with a prebent lordotic rod, the operator held the tong with right hand and gradually reduced the deformity to place the rod within the screw heads on the cranial part of osteotomy under close visual observation, with the support of the caudal part with left hand.

Results. The type of osteotomy performed was pedicle-subtraction osteotomy in 5 cases and anterior-release–posterior osteotomy in 2 cases. The mean correction angle was 39.7° (28°–63°) on the sagittal plane and 9.3° (0°–16°) on the coronal plane. The mean correction of the chin-brow vertical angle was 37.1° (18°–61°). There was no neurovascular complication.

Conclusion. Using the sterile-freehand reduction technique, the operator can obtain a safe, controlled reduction with close monitoring of the surgical field. The technique is potentially a simple and effective method to provide stable, 3-dimensional reduction for corrective osteotomies of the cervical spine.


Fixed kyphotic deformities of the cervical spine have various etiologies, including ankylosing spondylitis (AS), severe spondylosis, ossification of the posterior longitudinal ligament, and complications of previous surgery and trauma. However, a deformity of the cervical spine may cause more severe disabilities than one of the thoracolumbar spine, despite the low incidence of the former. Corrective osteotomy could alleviate not only clinical problems related to difficulty swallowing, poor skin and oral hygiene, and chronic neck pain originating from sagittal imbalance, but also social problems including restricted horizontal gaze and self image.

Previous reports of clinical outcomes after corrective osteotomy of the cervical spine have been excellent.[1–4] However, corrective osteotomy of the cervical spine is one of the most challenging procedures because of catastrophic complications such as irreversible spinal cord injury and possible brain damage from a vertebral artery injury, and this procedure is considered riskier than thoracolumbar osteotomy. The complication rates in previous reports range from 26.9% to 87.5%, including a 4.3% rate of permanent neurological complications and a 2.6% mortality rate.[4]

For a successful osteotomy, the first step is to remove the bony structure to release the fixed deformity sufficiently. The second step is to correct the deformity safely, and the final step is to maintain the corrected angle with stable fixation. The second step, reduction of the deformity, is the most critical step. Abrupt correction force on the destabilized spinal structure can result in translation or subluxation of the spinal column, causing impingement of the spinal cord and nerve roots.

Intraoperative manual reduction is the most commonly used technique in the literature.[2,3,5] This technique requires the surgeon to move out of the sterile surgical field and reduce the deformity holding a Mayfield clamp or halo ring while an assistant monitors the surgical field. Furthermore, it necessitates multiple releases and retightening of the clamp holding the unstable cervical spine. To avoid these inconveniences, the authors used the "sterile-freehand (SF)" reduction technique, a simple and controlled reduction for cervical osteotomy. The purpose of this study is to present the outcomes and effectiveness of this innovative SF reduction technique.