The reduction and direct repair of isthmic spondylolisthesis using the smiley face rod method in adolescent athlete: Technical note

Robotic-assisted minimally invasive repair surgery for progressive spondylolysis in a young athlete: a technical note

Presently, the invasiveness of direct repair surgery for lumbar spondylolysis is relatively high. Thus, high school and junior high school students who play sports often cannot return to sports before graduation because of the invasiveness. The use of a robotic system enabled an accurate and minimally invasive procedure. Robotic-assisted minimally invasive direct pars repair surgery is useful for young patients with progressive spondylolysis.

A Novel Technique for Pars Defect Direct Repair with a Modified Smiley Face Rod for Spondylolysis and Isthmic Spondylolisthesis

Introduction

Lumbar spondylolysis is a common fatigue fracture of the pars interarticularis of the lamina of the lumbar spine in adolescent athletes presenting with pars clefts. Some pseudarthrotic lumbar spondylolysis causes low back pain or radiculopathy. This study presents a case of pseudarthrotic lumbar spondylolysis that was successfully treated using a modified smiley face rod technique.

Technical Note

We developed a modified smiley face rod technique, which places pedicle screws in the lateral edge of the pedicle to preserve the erector spinae muscles and inserts a U-shaped rod between the spinous processes to preserve the supraspinous ligament. When a U-shaped rod penetrates the interspinous ligament subcutaneously, the resection of the supraspinous ligaments can be avoided. When the screw head is positioned more anterolaterally, a compression force is applied perpendicular to the surface of the pars cleft by rod clamping. This intrasegmental fusion technique preserves the mobile segment and simultaneously repairs the pars cleft. It is less invasive and more appropriate than interbody fusion for young athletes to avoid the possibility of future adjacent segment disorders.

Conclusions

This is a minimally invasive procedure that can easily achieve bone fusion and should be introduced for patients who are suffering from the symptoms of pseudarthrotic lumbar spondylolysis.

A Technical Pitfall of Decompression with Direct Repair of a Ragged Edge Using the Smiley-Face Rod Method : A Case Report

The smiley-face rod method has been reported to be a successful technique for reducing slippage and repairing pars defects in lumbar spondylolisthesis. However, we encountered a patient who developed right L5 radiculopathy with muscle weakness after use of the smiley-face rod method. The patient was a 19-year-old female judo player who had undergone direct repair surgery using the smiley-face rod method for terminal-stage lumbar spondylolysis. Postoperatively, she developed paresthesia on the lateral side of the right thigh with weakness of the right tibialis anterior and extensor hallucis longus. Computed tomography showed right foraminal stenosis at L5 with the floating lamina shifted ventrally and apophyseal ring fracture. In this case, the spondylolysis fracture angle differed between the left and right sides, with the fracture line on the right side running more sagittally. As a result, the floating lamina was shifted ventrally on the right side by compression and the right L5 intervertebral foraminal space was narrowed due to the ventral shift in the floating lamina and the apophyseal ring bone fragment. The shape of the fracture line should be examined carefully before surgery to avoid this technical pitfall. J. Med. Invest. 69 : 308-311, August, 2022.

Bone Formation During Correction of Vertebral Rounding Deformity in a Rat Model of Pediatric Spondylolisthesis

STUDY DESIGN

A study using rat spondylolisthesis models.

OBJECTIVE

The aim of this study was to elucidate the mechanism for correction of vertebral rounding deformity.

SUMMARY OF BACKGROUND DATA

Vertebral rounding deformity is the strongest risk factor for high-grade slippage associated with spondylolisthesis in adolescents. We previously reported that inadequate endochondral ossification of the anterior upper corner of the vertebral growth plate in response to mechanical stress could be the pathological mechanism of vertebral rounding deformity.

METHODS

We created a model of spondylolisthesis using 4-week-old rats. They were divided into a tail suspension group that underwent tail suspension to decrease mechanical stress starting at 2 weeks postoperatively and a ground control group with no intervention. Radiographs and microcomputed tomography scans were obtained once weekly for 6 weeks postoperatively. The lumbar spines were then harvested for histological analysis. Immunohistochemical studies detected types I, II, and X collagen in the growth plate cartilage. Bone histomorphometrical analysis was also performed.

RESULTS

Radiological and histological evidence in the ground control group showed progress the rounding deformity with time as previously reported. Formation of normal cancellous bone was observed radiologically over time in the tail suspension group, indicating correction of rounding deformity. Histologically, the site showing radiological evidence of correction was derived from cartilage tissue. After starting tail suspension, the growth plate stained positive for type X collagen and the corrected site stained for types II and X collagen in a mosaic pattern. Chondrocytes expressing types I and II collagen and tartrate-resistant acid phosphatase-positive cells were also present at the corrected site. Histomorphometrically, more endochondral bone was detected at the corrected site than in the posterior aspect of the normal growth plate.

CONCLUSION

Correction of vertebral rounding deformity was associated with improvement of chondrocyte differentiation; furthermore, there is possible involvement of a third mechanism, namely transchondroid bone ossification.Level of Evidence: N/A.

Surgical management of stress fracture of the contralateral pedicle in a baseball player with unilateral lumbar spondylolysis : A case report

We describe successful surgical treatment in a case of L5 unilateral spondylolysis with contralateral pedicle stress fracture that was not resolved by conservative treatment in a high-performing college baseball player. The 20-year-old man presented with left low back pain that stopped his sports activities. Over the previous year, he had experienced a couple of episodes of pain that subsided with cessation of sports but reappeared after a return to sports. Computed tomography and magnetic resonance imaging revealed a right terminal stage pars fracture and a left pedicle stress fracture at L5. The pain originated from the left pedicle fracture, with no pain from the right unilateral spondylolysis. Given that conservative treatment for 1 year had not been effective, we decided on surgical treatment. Bilateral pedicle screws and the smiley face rod method were applied, and both fractures subsequently healed. In the 2 years since the surgery, the patient has returned to sports and has the potential to become a professional player. J. Med. Invest. 67 : 382-385, August, 2020.

A Case of Nonconsecutive Multiple-level Lumbar Spondylolysis Successfully Treated with Single-level Repair of the Pars Interarticularis

Lumbar spondylolysis is commonly recognized at a single-level of the lumbar spine and frequently affects the L5 pars interarticularis unilaterally or bilaterally. Some reports have described multiple-level spondylolysis, most cases of which occur at consecutive lumbar segments. We herein present a rare case of lumbar spondylolysis involving nonconsecutive multiple-level segments; only eight such cases have been reported previously. A 38-year-old man presented with a 10-month history of chronic severe low back pain. Lumbar flexion–extension radiographs and computed tomography revealed spondylolysis at the level of L3 and L5, whereas no spondylolisthesis was present and the intervertebral disc spaces were maintained at all levels. Because 6 months of conservative management failed and repeated diagnostic blocks confirmed that the fracture of the L3 pars interarticularis was generating pain, repair of the bilateral L3 pars interarticularis with the smiley face rod method was performed. At the last follow-up 1 year after surgery, the patient had resumed normal life as a laborer and reported no back pain.