First rib abnormalities in association with cervical ribs: a cause for postoperative failure in the thoracic outlet syndrome

A Single Institution 30-Year Review of Abnormal First Rib Resection For Thoracic Outlet Syndrome

OBJECTIVES

Congenital abnormalities of the first rib (ABNFR) are a rare cause of thoracic outlet syndrome (TOS). The range of abnormalities have not been clearly documented in the literature. Surgical decompression in these patients presents with increased complexity secondary to anomalous anatomy. Our goal is to review an institutional experience of first rib resection (FRR) performed for ABNFRs, to present a novel classification system, and to analyze outcomes according to clinical presentation.

METHODS

A prospectively collected database was used to identify individuals with ABNFRs who underwent FRR for TOS between 1990-2021. These individuals were identified both by preoperative imaging and intraoperative descriptions of the first rib after resection. Demographic, clinical, perioperative and pathological data were reviewed. ABNFRs were classified into three categories according to anatomical criteria: (I) Hypoplastic, (II) Fused, and (III) Hyperplastic. Outcomes were rated using the standardized Quick Disability of Arm Shoulder and Hand Scores (QDS), Somatic Pain Scores (SPS) and Derkash Scores (DkS).

RESULTS

Among the 2200 cases of TOS, there were 19 patients (0.8%) with ABNFR who underwent FRR. Average age at surgery was 30.5 (range 11-74), including 13 men and 6 women. Presentations included 9 arterial (ATOS), 6 neurogenic (NTOS), and 4 venous (VTOS) cases. There were 6 class I, 6 class II, and 7 class III ABNFRs. Among 6 NTOS patients there were 4 abnormal nerve conduction tests and 5 positive anterior scalene muscle blocks. Among the 9 patients with ATOS, thrombolysis was attempted in 5 patients, and of these, 3 ultimately required surgical thrombectomy. Of 4 VTOS cases, 2 were managed with thrombolysis, and 2 with anticoagulation alone. The approach for FRR was transaxillary in all patients. Secondary procedures included 1 pectoralis minor tenotomy, 1 scalenectomy, and 1 contralateral rib resection. No major neurological or vascular complications occurred. There was 1 patient who required surgical evacuation of a hematoma. Intraoperative chest tube placement was required in 5 patients secondary to pleural entry during dissection. There was an overall improvement in symptoms over an average follow-up of 7.4 months. QDS reduced from 49.7 pre-op to 22.1 (p<.05). SPS improved from 3.4 pre-op to 1.8. DkS scores were good to excellent in 79% of patients. Residual symptoms were noted in 7, and ATOS accounted for 5 (70%) of these. All patients were able to return to work.

CONCLUSIONS

Despite increased complexity, ABNFRs may be safely resected via transaxillary approach with low incidence of complications, very good symptom relief, and excellent outcomes. Congenital ABNFRs may by classified into three categories (hypoplastic, fused, and hyperplastic) with a variety of presentations, including ATOS, NTOS, and VTOS. Classification of ABNFRs allows concise description of abnormal anatomy which facilitates comparison between series and provides direction for surgical management to ultimately optimize patient outcomes.

Thoracic outlet syndrome caused by synostosis of the first and second thoracic ribs: 2 case reports and review of the literature

We present 2 cases of combined arterial and neurogenic thoracic outlet syndrome triggered by trauma in patients with congenital synostoses of the first and second ribs. These patients were successfully treated with supraclavicular resection of the first and second ribs and scalenectomy. We review these cases and the associated literature on thoracic outlet syndrome and rib synostosis.

Cervical rib fracture: an unusual etiology of thoracic outlet syndrome in a child

Thoracic outlet syndrome in children is an extremely rare disorder. Only 5 previous reports were presented in the literature with a description of thoracic outlet syndrome in 8 children. In these cases, the diagnosis of a cervical rib was common. We describe a case of neurogenic thoracic outlet syndrome in a 9-year-old patient where the initial symptoms occurred 2 months after a fall. Clinically, the patient developed progressive pain, numbness and tingling along the inner surface of the left forearm and in the palmar surface of the fourth finger and lateral aspect of the fifth finger. A plain radiography showed a cervical rib fracture and an electrophysiologic study suggested the presence of left lower brachial plexus neuropathy. Her fractured cervical rib was resected through a supraclavicular approach. Her symptoms resolved completely in the postoperative period. Although very rare one should keep in mind the possibility of thoracic outlet syndrome in children, especially with a history of trauma over the shoulder girdle presenting with a cervical rib and a lower brachial plexopathy.

Recurrent neurogenic thoracic outlet syndrome

BACKGROUND

Although 90% of patients with neurogenic thoracic outlet syndrome (NTOS) experience "excellent" or "good" results after thoracic outlet decompression, recurrent symptoms may develop in certain patients.

METHODS

This is a retrospective review of patients with NTOS who developed recurrent symptoms of upper extremity/shoulder/neck pain, weakness and limitation of motion at least 3 months after initial relief of symptoms by surgical decompression. Diagnostic procedures and outcomes of reoperative surgery were assessed.

RESULTS

Among almost 500 patients undergoing initial successful thoracic outlet decompression for symptoms of NTOS during the last decade, 17 redeveloped classic NTOS symptoms (3 of them bilaterally) at intervals from 3 to 80 months (mean 18 months) after the initial operative procedure. Ultimate diagnoses included incomplete first-rib resection (n = 1), compression of the brachial plexus by an ectopic band (n = 1), persistent brachial plexus compression by an intact first (n = 2) or second (n = 1) rib, brachial plexus compression by the pectoralis minor tendon (n = 13) and adherent residual scalene muscle (n = 14). Anterior scalene muscle block was positive in 9 patients later found to have recurrent symptoms from adherent residual scalene muscle. Among these 20 cases of osseous or musculotendinous causes of recurrent NTOS, all had "excellent" or "good" results from repeat surgery to eliminate the underlying structural problem (removal of intact or residual rib, pectoralis minor tenotomy, brachial plexus neurolysis, or a combination of these).

CONCLUSIONS

Complete excision of cervical or first ribs and subtotal excision (instead of simple division) of the scalene muscles will decrease the incidence of recurrent NTOS. Pectoralis minor tenotomy should be considered part of complete thoracic outlet decompression. Anterior scalene muscle block accurately predicts outcome of reoperation for certain types of recurrent NTOS.

Two-surgeon approach to thoracic outlet syndrome: long-term outcome

An orthopaedic surgeon and a vascular surgeon jointly conducted 30 operations for thoracic outlet syndrome in 27 patients, having done the preoperative assessments in conjunction with a neurologist. Anterior scalenectomy was performed by the supraclavicular route except in one case where the infraclavicular route was used. The further surgical procedure was tailored to the abnormalities identified--i.e. resection of cervical rib or band, or medial scalenectomy. The first rib was spared. At median follow-up of 37 months (range 3-228) results were judged excellent or good on 26/30 sides (87%); on the three occasions when scalenectomy alone was performed, the results were only fair or poor. There were no major complications and no patient required reoperation. The long-term outcome in this series suggests that, with multidisciplinary assessment and two-surgeon operative treatment, good results can be obtained by the supraclavicular route without resection of the first rib.

Arterial complications of the thoracic outlet syndrome

OBJECTIVES

Arterial complications due to compression of the thoracic outlet are uncommon. The objective of this study was to review our fairly extensive experience with this problem with particular reference to its management.

METHODS

Patients entered into the Vascular Clinic database were reviewed over an 11 year period. Twenty six records were found. In 24 patients the vasculopathy was caused by a cervical rib (complete in 15) and in two by an anomaly of the first rib. In all patients the basic arteriopathy was a fibrous structure with a post-stenotic aneurysm in 13. Seventeen presented with a fixed pulse deficit; 13 had a palpable aneurysm and 12 had distal embolisation.

RESULTS

Two patients refused operation. In 22 with cervical rib, the rib was removed via a supraclavicular incision, an anterior scalenectomy was performed and the arterial pathology repaired on its merit, usually by vein graft replacement or bypass. In two with first rib anomalies these were resected by the transaxillary route. Twenty three patients have been followed for between 3 months and 10 years; 20 are cured and three have residual claudication.

CONCLUSIONS

Our results show that simple excision of the cervical rib via the supraclavicular route together with vascular reconstruction is adequate. This is in disagreement with the view of those who advocate routine excision of the first rib in addition to cervical rib excision.

Targeted disruptions of the murine Hoxa-4 and Hoxa-6 genes result in homeotic transformations of components of the vertebral column

It is becoming clear that Hox genes, which encode transcription factors of the Antennapedia homeodomain family, are key players in establishing the body plan of mammalian embryos. They have already been implicated in the formation of the central nervous system, tissues derived from neural crest, the vertebral column and the limbs. In order to examine the roles of hoxa-4 and hoxa-6 during development, mice with targeted disruptions in these genes were generated. Each shows homeotic transformation of cervical vertebrae, at positions that approximate the anterior borders of expression of these genes in the prevertebrae. Defects were not observed in other tissues that normally express these genes. Hoxa-4-/hoxa-4- mice show, with 100% penetrance, anterior transformations of the dorsal aspects of the third cervical vertebra by acquiring features normally associated with the second cervical vertebra. Mice homozygous for the hoxa-6 mutation show, with incomplete penetrance, even on opposite sides of the same animal, posterior transformations of the seventh cervical vertebra to the first thoracic vertebra. In addition, both hoxa-4-/hoxa-4- and hoxa-6-/hoxa-6- mice show variability in expressivity. These data indicate that alternative genetic pathways can partially, and at times completely, substitute for the function of these two genes. Other members of these two paralogous Hox families are good candidates for providing the substitutions. As paralogous genes lie on different chromosomes, it is possible to examine the degree of redundancy among these genes by intercrossing mice with the appropriate individual disruptions. The analysis of double, triple and even quadruple mutants should determine the ways in which these Hox genes interact in order to specify the multitude of tissues in a restricted region of the developing mouse embryo.