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

Disclosures

Spine. 2012;37(26):2145-2150. 

In This Article

Materials and Methods

A total of 7 consecutive patients who underwent corrective osteotomy of the cervical spine for fixed kyphosis by a single surgeon were enrolled. There were 5 men and 2 women, and the mean age was 52.6 (range, 38–76) years. Indications for the osteotomy were a fixed kyphotic deformity with restriction in activities of daily living. Radiographically, we analyzed C2–C7 sagittal Cobb angles, the coronal angle measured by the angle between the midline of the dens and the midline of the T1 vertebra. The chin-brow vertical angle was measured on the whole-spine standing lateral radiographs with full extension of both the hip and knee joints. Three-dimensional (3D) computed tomography was performed 6 months after the operation to confirm bony union of the osteotomy.

Intraoperatively, motor-evoked potential (MEP) was monitored by a neurophysiologist. The operative time, intraoperative blood loss, and clinical complications were also assessed.

Surgical Techniques

Position and Preparation of the Surgical Field Under general anesthesia, all cases except 1 were placed in the prone and reverse Trendelenburg position on a Jackson operating table with the horseshoe headrest (Figure 1A). One severe chin-on-chest case that could not be placed in the prone position underwent osteotomy in the seated position. The entire head was shaved and included in the sterile field. Sterile skin preparation was performed according to an imaginary line just above the external ear to the eyebrows for the application of Gardener-Wells tongs within the surgical field. To provide initial stability, a sterile rope was connected from the tong to a 15-pound weight at the cranial side of the patient, outside the sterile field. A sterile rope was passed from the surgical field to outside through a hole made in the surgical drapes (Figure 1B). To prevent the unsterile part of rope moving into the sterile field, the rope was fixed at the hole using a piece of sterile surgical incise drape (3M Ioban; 3M Health Care, St. Paul, MN). MEP monitoring electrodes were fixed with similar manners. After setting of traction, head was supported by the horseshoe headrest frame for additional stability during the procedures.

Figure 1.

The prone position of the patient before (A) and after (B) preparation of surgical fi eld. The entire head was included in the sterile fi eld and a sterile rope was passed and connected to traction through a hole made in the surgical drape.

Pedicle Subtraction Osteotomy For pedicle subtraction osteotomy (PSO), a routine posterior midline approach was taken. After dissection of the paravertebral muscles, pedicle screws with or without lateral mass screws were placed in the cervical spine, and pedicle screws were placed on the thoracic spine under fluoroscopic guidance. For the next step, 3-level laminectomies centered on the target vertebra and complete facetectomies of the levels above and below were performed. After pedicle subtraction with decancellation using a high-speed burr, osteotomes, and a bone curette, a thinned posterior wall of the vertebral body was removed with a reverse-angled curette protecting the dura and nerve roots. One case had a bony defect on the vertebral body, and thus the anterior iliac crest graft was first inserted through a routine Smith-Robinson approach.

Once the pedicle subtraction and decancellation procedure was finished on 1 side (usually the left), a temporary rod was applied before starting the other side to prevent unintentional fracture or translation.

Reduction: SF Reduction Technique After completing the osteotomy on the other side, setscrews at the caudal part of the osteotomy were fixed on a prebent rod at the desired angle for the osteotomy. The operator stood on the right side of the patient and held the tong with his/her right hand while an assistant removed the temporary rod on the left side (Figure 2 A, C).

Figure 2.

A sterile-freehand reduction technique. The operator holds the tong with his right hand (A) after fi xation of the temporary rod on 1 side (arrow in C) and the caudal part of the osteotomy with a prebent rod (arrowhead in C). After removal of the temporary rod, the operator gradually reduces the deformity both in coronal and sagittal planes (curved arrow in B) under close visual observation of the osteotomy gap, with the support of the caudal part of the osteotomy with his left hand (straight arrow in B). Final fi xation of the corrected position (D).

Next, the operator gradually reduced the sagittal and/or coronal deformity with his/her right hand to place the prebent lordotic rod within the screw heads while the assistant fixed the setscrews on the cranial part of the osteotomy. During the reduction, the operator's left hand holds the caudal part of the osteotomy (usually the T1 spinous process) with a towel clip to provide a support and a lever at the same time. After reduction, the traction rope and the headrest frame were adjusted by another unscrubbed assistant or anesthesiologist to support the reduced position. Finally, the rod on the other side was applied in the routine manner (Figure 2B, D). MEP was monitored throughout the entire procedure.

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