Sub-total (Cranial Wedge) Ostectomy for the Treatment of Impinging/overriding Spinous Processes

A new technique of subtotal (cranial-wedge) osteotomy has recently been published by the authors, alongside a series of 25 clinical cases of overriding and impinging spinous processes of the thoracolumbar vertebrae treated in this manner. The technique involves removal of only the cranial one third of each affected spinous process, as opposed to complete transverse amputation of alternate processes as previously described. The technique is based on observations of spinous process and lesion morphology with a rationale of maximizing preservation of normal architecture, and goals of producing functionally and cosmetically improved outcomes.

Following placement of radio-opaque markers under radiographic guidance, the surgical approach is via the dorsal midline. Skin and subcutis are incised and the supraspinous ligament divided sharply. The supraspinous ligament attachments are separated from the cranial portion of each spinous process using a periosteal eleveator, and the interspinous ligaments transected sharply cranial to each planned resection. An oscillating saw is used to resect the cranial wedge, commencing on the dorsal aspect of the spinous process at the junction between middle and cranial thirds of the bone. The trajectory of ostectomy is taken as close to dorso-ventral as possible, such that the ventral extent of the resection emerges just ventral to the extent of impingement. The resultant fragment is then removed, prior to closure of the supraspinous ligament in a simple continuous pattern using 5 metric Polyglactin 910. Skin is apposed using a continuous intradermal pattern of 3.5 metric Polyglactin 910, followed by steel skin staples. In the current series stent bandages were sutured over the incision using 5 metric sheathed braided polyamide.  [...]