Abstract

Introduction: Cervical kyphosis is failure of posterior osteo-ligamento-muscular restraint secondary to a deficient anterior column. Prospective studies of stand-alone anterior construct in correction and maintainence of cervical column that would otherwise require combined ant & post surgeries is sparse.

Objectives: To evaluate the role of stand-alone anterior surgery for cervical kyphosis, determine its efficacy and analyse complications.

Methods: 42 consecutive patients aged 6 – 70 yrs (Av 31.4 yrs) who had a Kyphosis angle of more than 100 with its apex between lower end-plate of C2 and C7 on a lateral x-ray and underwent anterior only surgery for cervical kyphosis over 6 yrs (2000–06) formed the population for this prospective study. The average follow-up was 2.2 yrs (1 – 5 yrs). The mean pre-op kyphosis was 20.820 (100 – 780). Etiology was tuberculosis in 25, dysplasia in 7, trauma in 6 and tumors in 4 cases respectively. 39 of the 42 patients had myelopathic signs. Mean pre-op mJOA score was 7.4 (0–11). A left anterior cervical approach was used in all cases. Modified manubriotomy was required in 5 cases to instrument the caudal vertebra. Tricortical iliac crest strut graft was used in 40 and cylindrical mesh cage in 2 cases. Correction of kyphosis was achieved by intra-op adjustment of the head assembly & controlled distraction. Post-operatively all wore cervical orthosis for 3 mo.

Results: 41 patients were available for analysis (1 lost for f/u). The average number of corpectomies required were 2.5 (1–4) and the mean anterior column defect reconstructed was 27.3mm (22–42mm). The average graft subsidence was 3mm (0–10mm). 2 patients required revision surgery within 6 weeks for implant failure/graft resorption. Fusion occurred in rest of 39 patients. No further graft subsidence was noticed at 4 years in 17 patients. Spontaneous fusion at 3 mo was seen in normal adjacent segment due to plate overlapping in 2 cases. The average correction achieved was 15.220 (−40–730). The mortality rate was 2.12% (1 case). Visceral complications occurred in 3 cases (esophageal perforation in 1 and recurrent laryngeal nerve palsy in 2). The mean post-operative mJOA score was 14 (9 – 17). There was 1 deep and 1 superficial infection.

Conclusion: Ant decompression & reconstruction with instrumentation facilitates neurological recovery restoring alignment. Intra-op maneuvering allows the graft to be placed in an optimal position that allows fusion under compression.

Introduction: Formulation of surgical protocol in CSM is marred by the diversity in clinico-radiological presentation. Prospective data that assigns a specific surgery with identifiable similarities in clinico-radiological attributes is sparse.

Objectives:

To identify radiological patterns of compression (POC) of the spinal cord

Methods: 135 consecutive patients aged 32–75 yrs (mean 48.1yr) operated for CSM from 1999–2005 formed the study group for this prospective series. The objectives were to identify radiological patterns of compression (POC), develop a surgical algorithm based on POC and evaluate outcome. Four POC were identified on MRI.

Pattern I – predominant one/two level compression in normal/narrow canal

Mean follow-up was 3 yrs (2–8). ACDF was performed for patterns I, II & III and posterior decompression for pattern IV and III(A). For pattern IV(A), a two stage primary posterior decompression followed by targeted ACDF at the site of maximal compression was performed. The clinical outcome was measured by modified JOA (mJOA) score, Hirayabashi Recovery Rate (HRR) and functional outcome by modified Neck Disability Index (NDI).

Results: The mean pre & post-op mJOA score was 10.40±3.33 & 15.76±1.45 respectively with average HRR of 80.10 ± 26.38. The difference in the mJOA scores was statistically significant (unpaired t test) for each POC. In multilevel CSM, anterior surgery in POC type III had statistically better post op mJOA as compared to those who underwent posterior surgery viz POC types IV and III & IV variants although the difference in their HRR and NDI were not statistically significant.

Conclusion: Anterior surgery has better neurological outcome in judiciously selected patients with multilevel CSM. Surgical decision-making guided by patterns of compression (POC) is pivotal for optimal functional outcome.