Sagittal Spine Length Measurement: A Novel Technique to Assess Growth of the Spine

STUDY DESIGN

The accuracy and repeatability of a novel sagittal spine length (SSL) radiographic measurement was examined using photographic and radiographic imaging.

OBJECTIVES

To validate the new SSL technique for measuring growth in early-onset scoliosis (EOS) patients.

SUMMARY OF BACKGROUND DATA

Current assessment of patient growth undergoing growth-friendly surgical treatment for EOS is the use of serial vertical spine height measurements (VH) on coronal radiographs. Spine-based distraction implants are able to control the coronal plane deformity of scoliosis, but exhibit a "law of diminishing returns" in the impact of each follow-up lengthening surgery. As these treatments are kyphogenic, we hypothesize that the increase in kyphosis is, in fact, growth out of plane, not captured by standard spine height measurements.

METHODS

Measurement accuracy was assessed using 6 spine model alignments and clinical radiographs of 23 retrospective EOS patients. Inter- and intrarater reliabilities were assessed using interclass coefficient (ICC) analyses. The discrepancy between the VH and SSL was also investigated.

RESULTS

The model assessment showed excellent accuracy, with a 1.54 mm (SD: 1.07, range: 0.03-3.14, p = .226) mean error and mean ICCs of 0.999. As the kyphosis increased, a progressive difference between the phantom VH and SSL was observed. Interrater reliability ICCs of the clinical radiographs averaged 0.981 and 0.804, whereas intrarater reliabilities averaged 0.966 and 0.826, for the coronal and sagittal radiographs, respectively. Mean clinical SSLs were 177.5 mm (SD: 28.5, range: 114.3-250.3), whereas the VH averaged 161.6 mm (SD: 31.8, range: 58.5-243.0), resulting in a 16.0-mm (SD: 16.7, range: 0.3-90.3, p < .0001) difference between the two measurements with a progressive difference as the kyphosis increased.

CONCLUSIONS

The novel SSL measurement is accurate, repeatable, and complements the current growth assessments for EOS treatments. Until sagittal spine lengths are taken into consideration, the "law of diminishing returns" should be interpreted with caution.

LEVEL OF EVIDENCE

Level II - Prospective Comparative Study.

The accessory soleus muscle as a cause of persistent equinus in clubfeet treated by the Ponseti method : A report of 16 cases

Encountering an accessory soleus muscle in children undergoing surgical release for clubfeet is not a frequent occurrence and only a few reports could be traced in literature. The purpose of this study is to report a series of 20 observations in 16 patients with idiopathic clubfeet treated by the Ponseti technique where the accessory soleus muscle was responsible in preventing full ankle dorsiflexion after Achilles tendon tenotomy. Following its division, adequate dorsiflexion could be achieved. To our knowledge this is the largest series published to date on this topic. In addition, we discuss the frequency and epidemiology, as well as the anatomy of the accessory soleus muscle, its innervation and embryology. The mean age at presentation was 40.7 days (range : 6 to 210 days). The accessory soleus tendon was observed in 6 right and 6 left feet, 4 feet had bilateral involvement. The average ankle dorsiflexion after complete tendo Achilles tenotomy was 2.50 (SD: 638), and after sectioning of the accessory soleus tendon, it was 19.50 (SD: 559) (p < 0.001). Correction was obtained in all patients, after 3 to 10 casts. In conclusion, the recognition of an accessory soleus muscle, in patients with clubfeet, is important, and its release is necessary to fully correct the deformity. Failure to recognize this muscle may lead to persistent hindfoot deformity.