A Case of Endoscopic Partial Transverse Process and Sacral Alar Resection for Bertolotti's Syndrome and Continued Basketball Playing Two Years After Surgery

Abstract

Bertolotti's syndrome is a syndrome in which the transverse process of the most caudal lumbar vertebra becomes enlarged and articulates with the sacral alar, causing back pain. Here, we report a case of an adolescent basketball player with Bertolotti's syndrome who was unable to resume playing despite conservative treatment and underwent an endoscopic partial transverse process and sacral alar resection. A 16-year-old male basketball player presented to our hospital with a chief complaint of left low back pain during exercise and prolonged sitting for over one month. No obvious neurological abnormality was found. X-rays and CT showed lumbosacral transitional vertebrae, and the left transverse process of the sixth lumbar vertebra articulated with the sacrum and iliac, which was the Castellvi classification IIA. A block injection into the articulated surface produced improvement in pain, but the effect was not sustained. Since the patient was refractory to conservative treatments, such as medication and physiotherapy, surgery was performed. During surgery, the articulated transverse process and sacral alar were partially resected endoscopically. Because of the proximity of the resection site to the S1 nerve root, intraoperative electromyography (free-run EMG) was used to detect nerve root irritation symptoms in real time. The patient had no postoperative complications, his low back pain improved immediately, and he returned to play basketball three months after surgery. One year after surgery, the bone resection site showed gradual bone regeneration, and two years after surgery, the transverse process and sacral alar showed a bony bridge. The transverse process was enlarged compared to immediately after surgery but remained smaller than that before surgery. The patient continued to play basketball for two years after surgery without back pain, and no symptoms due to bone regeneration appeared. In the present case, a partial resection of the transverse process and sacral alar was performed with good results. Because the bone resection site was close to the S1 nerve root, the use of an endoscope and intraoperative free-run EMG allowed for a safer procedure during the bone resection. In addition, the patient did not present with symptoms that would affect his basketball performance, although the bone regenerated and bridging occurred between the transverse process and sacral alar over a two-year postoperative course.

Keywords: articulation of the transverse process with the sacral alar and iliac crest; basketball; bertolotti’s syndrome; bone regeneration; bone resection; castellvi classification iia; endoscopic surgery; intraoperative electromyography; low back pain; minimum invasive surgery.

Figure 1. Imaging findings at the initial examination

a: Plain X-ray anteroposterior view showed an enlargement of the left transverse process of the sixth lumbar vertebra. b: CT coronal view showed the left transverse process of the sixth lumbar vertebra articulating with the sacral alar and iliac bone (white arrow). c: CT 3D image showed that the left transverse process of the sixth lumbar vertebra was continuous with the sacral alar (white arrow). d: MRI T2-weighted sagittal view showed no intervertebral disc degeneration. e: MRI STIR coronal view showed no fatigue fracture of the sacral alar. f: MRI T2-weighted coronal view showed abnormal left S1 nerve root migration (white arrow).

Figure 2. Imaging finding of block injection

Contrast-containing block injection was performed on the articulated site between the transverse process and sacral alar.

Figure 3. Surgical findings

a: Endoscopic bone resection of the dorsal site of the transverse process. b: Bone resection was performed anterior to the sacrum under endoscopy. c: Resection was performed while confirming the endoscopic position between the transverse process and sacral alar in the fluoroscopic lateral view. d: Fluoroscopic lateral view confirmed that the resection reached the anterior sacrum.

Figure 4. Immediate postoperative imaging findings

a: Plain X-ray anteroposterior view showed dissection of the bony continuity of the transverse process and the sacral alar or iliac crest. b: CT coronal view image showed adequate bone resection (white arrow). c: CT 3D image showed dissection of the bony continuity between the transverse process and the sacral alar or iliac crest (white arrow).

Figure 5. One-year postoperative imaging findings

a: Plain X-ray anteroposterior view showed bony regeneration around the transverse process. b: CT coronal view showed bone regeneration of the transverse process and sacral alar (white arrow). c: CT 3D image showed no bony continuity of the transverse process and sacral alar or iliac crest (white arrow).

Figure 6. Imaging findings two years after surgery

a: Plain anteroposterior X-ray showed further bony regeneration around the transverse process. b: CT coronal view showed bony continuity of the transverse process and sacral alar (white arrow). c: CT 3D image showed bony continuity of the transverse process and sacral alar (white arrow).