Complications following anterior approaches to the cervical spine: Review of 535 surgical procedures

Anatomic Relationship Between Right Recurrent Laryngeal Nerve and Cervical Fascia and Its Application Significance in Anterior Cervical Spine Surgical Approach

STUDY DESIGN

An anatomic study of anterior cervical dissection of 42 embalmed cadavers.

OBJECTIVE

The aim was to study the anatomic relationship between recurrent laryngeal nerve (RLN) and cervical fascia combined with the requirements in anterior cervical spine surgery (ACSS).

SUMMARY OF BACKGROUND DATA

There has been no systematic research about how to avoid RLN injury in anterior cervical spine surgical approach from the aspect of the anatomic relationship between RLN and cervical fascia.

METHODS

Forty-two adult cadavers were dissected to observe the relationships between RLN and different cervical fascia layers.

RESULTS

RLN pierced out the alar fascia from the inner edge of the carotid sheath in all cases, and the piercing position in 22 cases (52.4%) was located at the lower segment of T1. The enter point into visceral fascia of RLN was located at C7-T1 in 25 cases (59.5%). The middle layer of deep cervical fascia exhibited the most stable anatomic relationship with RLN at the carotid sheath confluence site. Pulling visceral sheath leftwards would significantly increase the RLN tension.

CONCLUSION

Using the close and stable relationship between RLN and cervical fascia could help to avoid RLN injury in anterior cervical spine surgical approach.

LEVEL OF EVIDENCE

4.

Vocal cord palsy after anterior cervical spine surgery: a qualitative systematic review

BACKGROUND CONTEXT

Vocal cord palsy (VCP) is a known complication of anterior cervical spine surgery. However, the true incidence and interventions to minimize this complication are not well studied.

PURPOSE

To conduct a systematic review to identify the incidence, risk, and interventions for VCP after anterior cervical spine surgery.

STUDY DESIGN

This is a qualitative systematic literature review.

SAMPLE

Prospective and retrospective trials of patients undergoing anterior cervical spine surgery that reported on postoperative VCP or recurrent laryngeal nerve palsy.

OUTCOME MEASURES

Primary: incidence of VCP after anterior cervical spine surgery; secondary: risk factors and interventions for prevention of VCP after anterior cervical spine surgery.

METHODS

Electronic searches were conducted on Ovid Medline, EMBASE, Cochrane Central Register of Controlled Trials, and Cochrane Database of Systemic Reviews for clinical studies reporting VCP in anterior cervical spine surgery, limited to studies published between 1995 and June 2013 in English and French languages. After selection of studies independently by two review authors, data on incidence, risk, and interventions were extracted. Qualitative analysis was performed on three domains: quality of studies, strength of evidence, and impact of interventions.

RESULTS

Our search has identified 187 abstracts, and 34 studies met our inclusion criteria. The incidence of VCP ranges from 2.3% to 24.2%. Significant heterogeneity in study design and definition of VCP were used in the published studies. There is good evidence that reoperation increases the risk of VCP. One study of moderate strength suggests that operating from the right side may increase the risk of VCP. Among the interventions studied, endotracheal tube (ETT) cuff pressure monitoring with deflation during retraction has shown to reduce the incidence from 6% to 2%, but this result was not confirmed by randomized control trials. Limited evidence exists for other interventions of intraoperative electromyographic monitoring and methylprednisolone.

CONCLUSIONS

Vocal cord palsy is a significant morbidity after anterior cervical surgery with incidence up to 24.2% in the immediate postoperative period, with a higher risk in reoperation of the anterior cervical spine. Moderate evidence exists for ETT cuff pressure adjustment in preventing this complication.

Síndrome do disco adjacente à fusão (Síndrome de Transição) na coluna cervical: resultados segundo critérios clínicos e radiológicos

OBJETIVO: o objetivo deste trabalho foi identificar a ocorrência da síndrome do disco adjacente secundária à fusão intervertebral, no segmento cervical, e os fatores prognósticos associados. MÉTODOS: foram analisados os prontuários e exames de imagem de 209 indivíduos submetidos ao tratamento cirúrgico da doença degenerativa cervical, sendo 169 casos por via anterior e em 40 por via posterior, no HC-FMUSP, no período de março de 1993 a janeiro de 2007. A avaliação clínica foi quantificada pela escala da Japanese Orthopaedic Association (JOA), com média de segmento de 80 meses. A análise radiológica foi baseada nos critérios de instabilidade de White e Panjabi em todos os casos. A degeneração discal foi mensurada segundo a escala de Kellgren antes e após a cirurgia. RESULTADOS: no total, diagnosticou-se a síndrome do disco adjacente em 30 casos (17,75%), com média de intervalo de tempo de incidência de 28,5 meses após a fusão ou 2,9 casos/ano. Houve um aumento das alterações degenerativas nos exames radiológicos em níveis adjacentes à fusão por via anterior em 41,42% e em 52,5% por via posterior sem fusão, avaliados pela escala de Kellgren, com taxa de degeneração de 6,7% ao ano, sem correlação com alterações clínicas. CONCLUSÕES: alterações no alinhamento fisiológico sagital da coluna e a sua gravidade predispõem ao desenvolvimento da síndrome. Não foi observada incidência da síndrome em casos de pseudoartrose ou utilização de metacrilato, portanto onde não ocorreu a fusão. A utilização de descompressão e fusão, por via anterior, está associada à possibilidade de desenvolvimento de um novo quadro de mielorradiculopatia no período pós-operatório. Fusão em um nível que envolva a quinta ou sexta vértebras cervicais, fixação com placas e pré-existência da evidência radiográfica de degeneração de disco adjacente mostraram-se como os grandes fatores de risco para o seu surgimento.