Complex osteotomies vertebral column resection and decancellation

Pedicle subtraction osteotomy (PSO) is nowadays widely used to treat sagittal imbalance. Some complex malalignment cases cannot be treated by a PSO, whereas the imbalance is coronal or mixed or the sagittal imbalance is major and cannot be treated by a single PSO. The aim of this article was to review these complex situations--coronal imbalance, mixed imbalance, two-level PSO, vertebral column resection, and vertebral column decancellation, and to focus on their specificities. It wills also to evoke the utility of navigation in these complex cases.

The lumbar lordosis index: a new ratio to detect spinal malalignment with a therapeutic impact for sagittal balance correction decisions in adult scoliosis surgery

PURPOSE

Sagittal malalignment is frequently observed in adult scoliosis. C7 plumb line, lumbar lordosis and pelvic tilt are the main factors to evaluate sagittal balance and the need of a vertebral osteotomy to correct it. We described a ratio: the lumbar lordosis index (ratio lumbar lordosis/pelvic incidence) (LLI) and analyzed its relationships with spinal malalignment and vertebral osteotomies.

METHODS

53 consecutive patients with a surgical adult scoliosis had preoperative and postoperative full spine EOS radiographies to measure spino-pelvic parameters and LLI. The lack of lordosis was calculated after prediction of theoretical lumbar lordosis. Correlation analysis between the different parameters was performed.

RESULTS

All parameters were correlated with spinal malalignment but LLI is the most correlated parameter (r = -0.978). It is also the best parameter in this study to predict the need of a spinal osteotomy (r = 1 if LLI <0.5).

CONCLUSION

LLI is a statistically validated parameter for sagittal malalignment analysis. It can be used as a mathematical tool to detect spinal malalignment in adult scoliosis and guides the surgeon decision of realizing a vertebral osteotomy for adult scoliosis sagittal correction. It can be used as well for the interpretation of clinical series in adult scoliosis.

Proximal end clavicle fracture from a parachute jumping injury

Fractures of the medial end of the clavicle are the least common type of clavicle fracture. We report a 29-year-old military parachutist who presented with medial end clavicle fracture after a bad landing. He was first treated non-operatively in a tertiary center and was then referred to our center by his general practitioner. Surgery was indicated since the fracture was displaced and the patient needed anatomical reconstruction to promote rapid bone healing and a prompt return to work. The medial fragment being comminuted, K-wires were used for internal fixation instead of a plate. The two K-wires were bent 180° to avoid risk of migration and were removed 3 months after surgery when the patient had begun to perform all activities without pain. Aggressive treatment is recommended for medial end clavicle fracture in case of displacement and facilitates rapid functional recovery, notably in patients with considerable clavicular demand.

Incidental durotomy during spine surgery: incidence, management and complications. A retrospective review

STUDY DESIGN

Retrospective review of a series of patients who underwent spinal surgery at a single spine unit during a 1 year period.

OBJECTIVES

To assess the incidence, treatment, clinical consequence, complications of incidental durotomy during spine surgery and results of 37 months clinical follow-up.

SUMMARY OF BACKGROUND DATA

Incidental durotomy is an underestimated and relatively adverse event during spinal surgery. Several consequences of inadequately treated dural tears have been reported.

METHODS

A retrospective review was conducted on 1326 consecutive patients who underwent spinal surgery performed in one French spine unit from January 2005 to December 2005. We excluded from this study patients treated for emergency spine cases.

RESULTS

Fifty-one dural tears were identified (3.84%). Incidental durotomies were associated with anterior cervical approach in 1 case, with posterior cervical approach in 1 case, with anterior retroperitoneal approach in 1 case and with posterior thoracolumbar approach in 48 cases. In addition, any clinically significant durotomy unrecognised during surgical procedure were included. Thirteen patients presented postoperative complications including 7 cerebrospinal fluid leaks, 2 wound infections, 2 postoperative haematomas, and 2 pseudomeningoceles. Nine of these 13 patients required a revision procedure. A mean follow-up of 37 months showed good long-term clinical results.

CONCLUSIONS

Incidental durotomy is a common complication of spine surgery. All incidental durotomies must be repaired primarily. Dural tears that were immediately recognised and treated accordingly did not lead to any significant sequelae at a mean follow-up of 37 months. However, long-term follow-up studies will be needed to confirm this finding. The risks associated with dural tears and cerebrospinal fluid leaks are serious and should be discussed with any patients undergoing spine surgery.

Heterotopic ossification after cervical disc replacement: clinical significance and radiographic analysis. A prospective study

Limited data is available regarding heterotopic ossification (HO) after cervical disc replacement (CDR). The goal of this study was to determine the incidence of HO after CDR with the Mobi-C artificial disc to identify the risk factors for HO, and to investigate whether HO affects clinical outcome and range of motion (ROM). Seventy one patients were included in this study. The mean follow-up was 21 months. Radiological evaluation included grading of HO and assessment of ROM for each level treated. HO was detectable in 23 treated segments (27.7%). The mean ROM was 8.1 degrees preoperatively and increased to 10.2 degrees at the last follow-up visit. Nevertheless, HO did not appear to affect clinical outcomes. HO appears to be a common complication after CDR. No specific risk factors have been clearly identified in our study. Long-term follow-up will be needed to assess the clinical significance of HO.

Global analysis of sagittal spinal alignment in major deformities: correlation between lack of lumbar lordosis and flexion of the knee

INTRODUCTION

It has become well recognised that sagittal balance of the spine is the result of an interaction between the spine and the pelvis. Knee flexion is considered to be the last compensatory mechanism in case of sagittal imbalance, but only few studies have insisted on the relationship between spino-pelvic parameters and lower extremity parameters. Correlation between the lack of lumbar lordosis and knee flexion has not yet been established.

MATERIALS AND METHODS

A retrospective study was carried out on 28 patients with major spinal deformities. The EOS system was used to measure spinal and pelvic parameters and the knee flexion angle; the lack of lumbar lordosis was calculated after prediction of lumbar lordosis with two different formulas. Correlation analysis between the different measured parameters was performed.

RESULTS

Lumbar lordosis correlated with sacral slope (r = -0.71) and moderately with knee flexion angle (r = 0.42). Pelvic tilt correlated moderately with knee flexion angle (r = 0.55). Lack of lumbar lordosis correlated best with knee flexion angle (r = 0.72 and r = 0.63 using the two formulas, respectively).

CONCLUSION

Knee flexion as a compensatory mechanism to sagittal imbalance was well correlated to the lack of lordosis and, depending on the importance of the former parameter, the best procedure to correct sagittal imbalance could be chosen.

Correlation of clinical outcome and spinopelvic sagittal alignment after surgical treatment of low-grade isthmic spondylolisthesis

INTRODUCTION

The aim of this prospective study was to assess the sagittal alignment of the spine and pelvis before and after surgical treatment of isthmic spondylolisthesis with flat sacrum. At the same time, the functional outcome was analyzed and correlation examined.

MATERIALS AND METHODS

This study comprises analysis of 30 subjects (mean age 43 years) with isthmic spondylolisthesis and an average follow-up of 2.5 years after posterior spinal fusion. Radiological spinopelvic parameters were measured and functional evaluation was made using the Oswestry Disability Index.

RESULTS

Significant improvement toward more normal values for PT and SS in relation to PI was observed after surgery. Pelvic incidence was unaffected by surgery. Correction of the spinosacral angle shows that the anterior tilt with anterior sagittal imbalance due to spondylolisthesis may be corrected by reduction and fusion of the slipped level. Functional outcome was satisfactory with a statistically significant difference between preoperative values and final follow-up values. The sub-group of patients with insufficient restoration of sagittal balance parameters had less good outcomes than the others.

DISCUSSION AND CONCLUSION

Surgical management of low- and mid-grade isthmic spondylolisthesis showed good clinical outcome with restoration of correct values for the pelvic position-dependent parameters, i.e., pelvis tilt, sacral slope, C7 plumb line position and SSA.

Safe working zones using the minimally invasive lateral retroperitoneal transpsoas approach: a morphometric study

PURPOSE

The minimally invasive lateral retroperitoneal transpsoas approach is a recent technique developed for lumbar interbody fusion and discectomy. The proximity of the retroperitoneal vessels and ventral nerve roots to the surgical pathway increases the risk of injury to these anatomical structures. A precise knowledge of the regional anatomy of the lumbar plexus is required for safe passage through the psoas muscle. Preoperative examination of the axial MRI images will allow the surgeon to observe the neural structures at the operative levels and confirm that abdominal vessels do not obstruct the lateral disc space. The objective of this study was to determine the anatomic position of the ventral nerve roots and the retroperitoneal vessels in relation to the vertebral body in the degenerative spine and to delineate a safe working zone using magnetic resonance imaging (MRI).

METHODS

We retrospectively evaluated lumbar spine MRI in 78 patients (from L1-L2 to L4-L5). The total number of lumbar vertebrae measured was 304 levels. Sagittal MRI sections were used to measure disc height (anterior, middle, posterior). Axial MRI sections were used to measure the sagittal and transversal vertebral endplate diameters, the overlap between ventral nerve roots and the posterior border of the lower endplate of the vertebral body, and the overlap between the retroperitoneal vessels and the anterior border of the lower endplate of the vertebral body. The safe zone was subsequently calculated. It was defined as the relative lower endplate vertebral body sagittal diameter that is anterior to the nerve root and is posterior to the retroperitoneal vessels.

RESULTS

The safe working zone was 75.3% of the lower endplate of the vertebral body sagittal diameter at L1-L2, 59.5% at L2-L3, 51.9% at L3-L4 and 37.8% at L4-L5 levels. This area significantly decreases from L1-L2 to L4-L5 (p < 0.05). Compared with L1-L2, L2-L3 levels, the more anterior position of the nerve root and the more posterior position of the retroperitoneal vessels at the L4-L5 level causes a significant reduction of this area. Compared with the L3-L4 level, we observed that the safe zone decrease was simply secondary to the more anterior position of the nerve roots at the L4-L5 level.

CONCLUSION

Preoperative planning and safe zone delineation are a simple method to assess the relative position of neural and vascular anatomic structures in relation to the surgical area. This method can help spine surgeons to prevent perioperative complications.

Total hip replacement pseudotumoral osteolysis

We report three cases of pseudotumoral lesion secondary to total hip replacement using metal on polyethylene bearings, presenting two distinct macroscopic aspects: (a) classic inflammatory granuloma and, in one case, (b) onset of hematoma associated with gluteal vessel lesions, probably affected by the pseudotumoral process. Diagnosis was radiographic, with CT-scan serving to confirm and, more importantly, to reveal extension and analyze surrounding tissue. Arteriography is needed when the lesion is liquid, and biopsy may be envisaged depending upon the clinical situation. In all three cases, histology was typically that of granulomatous lesions related to wear debris. Once diagnosis could be established, treatment was similar in both presentations, with surgical revision, which should be as early as possible in case of cortical bone involvement, to prevent pathologic fracture.

Lipoma in the cerebellopontine angle

A case of lipoma in the cerebellopontine angle is reported. Intracranial lipomas are very rare, especially in the cerebellopontine angle. To our knowledge, only four cases, including our own, have been operated upon. Until now, total extirpation has not been possible. The singular appearance on computed tomography scanning of this dysembryoplasia is presented together with a bibliography of this subject.