and Nicholas T. Zervas, M.D.

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Combined Approach to "Dumbbell" Intrathoracic and Intraspinal Neurogenic Tumors Hermes C. Grillo, M.D., Robert G. Ojemann, M.D., J. Gordon Scannell, M.D., and Nicholas T. Zervas, M.D. ABSTRACT The unexpected finding of an extension of a neurogenic tumor from the thorax through the spinal foramen into the neural canal complicates its removal.

1 Combined Approach to "Dumbbell" Intrathoracic and Intraspinal Neurogenic Tumors Hermes C. Grillo, M.D., Robert G. Ojemann, M.D., J. Gordon Scannell, M.D., and Nicholas T. Zervas, M.D. ABSTRACT The unexpected finding of an extension of a neurogenic tumor from the thorax through the spinal foramen into the neural canal complicates its removal. Serious neurological complications may result from a two-stage approach, whether done first through the thorax or neural canal. Vertebral tomography or computed tomographic scanning reveals enlargement of a spinal foramen in advance of operation. Myelography confirms the probable presence of an intraspinal component. Four patients have been operated on using an approach designed to allow wide posterolateral thoracotomy and concomitant laminectomy for singlestage removal of the entire tumor. In 3 patients the diagnosis was schwannoma and in 1, neurofibroma. All had good results. Neurogenic tumors of the mediastinum may have an intraspinal component connected by a narrowed segment of tumor in the intervertebra1 foramen, hence the descriptive term dumbbell. In 1978, Akwari and associates [l] found that 69 patients (9.8%) out of 706 reported with mediastinal neurogenic tumors had extension through an intervertebral foramen. Most often, neurogenic tumors are discovered on an incidental chest roentgenogram as an intrathoracic mass of regular contour located in the posterior gutter. Neurological symptoms occur in more than 60% of patients with an intraspinal component. If laminectomy alone is performed as a firststage procedure, serious complications may result [l]. The unexpected intraoperative finding of extension of tumor through the spinal fora- From the General Thoracic Surgical Unit and the Neurosurgical Service, Massachusetts General Hospital, and the Departments of Surgery and Neurosurgery, Harvard Medical School, Boston, MA. Presented at the Nineteenth Annual Meeting of The Society of Thoracic Surgeons, San Francisco, CA, Jan 17-19, Address reprint requests to Dr. Grillo, Massachusetts General Hospital, Boston, MA men complicates a thoracic approach. Undue traction on this extension may lead to spinal cord damage. Hemorrhage at the vertebral foramen may be difficult to control [l]. In this circumstance, the surgeon may elect to transect the tumor at the foramen and leave the removal of the intraspinal portion for a later neurosurgical operation. Therefore, it is important to make the diagnosis of intraspinal extension prior to planning the surgical procedure. Roentgenograms of the thoracic spine and polytomography or computerized axial tomography of the appropriate region should be done. If there is any suggestion of widening of the intervertebral foramen, myelography is indicated. Once the diagnosis of a "dumbbell" tumor has been established, careful planning of the operation is required. We have used a combined thoracic-neurosurgical approach that allows excision of both components of the tumor under direct vision in a single operation through a single skin incision. If the tumor is located in the lower thoracic region, spinal arteriography is done. Material and Method Technique of Operation The patient is placed on a tilt table in the lateral thoracotomy position. The field is draped widely. The incision has a vertical component over the middle of the spinous processes, beginning approximately 5 cm above the level of the foramen to be explored and extending for about 5 cm below this (Fig 1). The incision curves sharply at this point to a sloping transverse line, which sweeps forward to become a standard posterolateral thoracotomy incision at the level of the scapular tip. A flap of skin and subcutaneous tissue is raised over the muscular fascia. Thoracotomy is completed beneath this flap. The latissimus dorsi muscle is divided at the usual level, and the trapezius muscle is divided as necessary. The interspace is selected with ref- 402

2 403 Grillo et al: "Dumbbell" Intrathoracic and Intraspinal Tumors Fig 1. Skin incision. The vertical component, which permits laminectomy, is centered at the level of the involved foramen (X) and extends for about 10 cm. It curves forward to join the anterior portion of the thoracotomy incision. The dotted line indicates the thoracotomy beneath the Pap. erence to the foramen involved. For a high lesion, the fourth interspace or the bed of the fourth rib usually will be adequate. Higher ribs may be divided posteriorly for very large lesions at high levels. The intrathoracic portion of the tumor is completely mobilized so that it is attached only by its intraforaminal isthmus. The neurosurgical portion of the operation follows; the vertical portion of the skin incision is used for a posterior approach to the spinal canal by laminectomy. The tumor may be entirely extradural. If not, the dura is opened laterally over the tumor and its intraspinal component separated from the spinal cord using microsurgical techniques. The nerve root entering the tumor is divided. The foramen may be enlarged if necessary to deliver the tumor intact into the thorax. If possible, the dura is closed and a pleural flap is used to seal the foramen in order to prevent leakage of spinal fluid. The entire operation of excising the tumor is carried out under direct vision, which minimizes the risk of disabling hemorrhage and neurological injury. Cuse Reports Four patients have been approached in this way. In 3, laminectomy was necessary. In 1, the foramen was eroded but the spinal projection could be extracted into the thoracic field. Following operation, all patients have done well for between two and one-half and eight years. PATIENT 1. A 34-year-old physician was discovered on routine study to have a mass in the right chest. Tomograms demonstrated enlargement of the neural foramen at the T-3 level with erosion of the posterior aspect of the vertebral body contiguous with the intrathoracic mass (Fig 2). A myelogram showed a small extradural defect at the same level on the right. There were no clinical signs of cord compression. Operation was done through the incision described, using the fourth intercostal space. The tumor mass based at the second interspace measured 4 cm in its greatest diameter. The sympathetic trunk and the second intercostal nerve that entered the tumor were divided above, below, and distally. Laminectomy of the third vertebral lamina and part of the second was done through the posterior midline ap-, proach. The T-2 nerve root was divided proximal to the tumor. The tumor directly involved the epidural vessels. Bleeding from these was controlled directly. A pleural flap was sutured over the foramen. Recovery was uneventful. Pathological diagnosis was schwannoma (neurilemoma). PATIENT 2. A 49-year-old woman had noted pain in the left subscapular area for more than two months with occasional numbness and aching in the left arm. Aching discomfort and tingling on the volar surface of the forearm gradually developed and extended into the hand to involve all five fingers. The left pupil was smaller than the right but reacted to light. The left palpebral fissure was smaller than the right. Chest roentgenogram demonstrated a 4 cm mass in the apex of the left chest with erosion of the lateral aspect of the first and possibly the second thoracic vertebral bodies. Frontal and lateral polytomographic sections showed expansion of the neural foramen between T-1 and T-2. The pedicle on the left side was extensively eroded. Thoracic myelogram showed a left dorsolateral epidural defect at the level of the T-1 root. The vertical portion of the incision was centered at the level of T-3 and extended in the midline to the level of C-5. The thorax was en-

404 The Annals of Thoracic Surgery Vol 36 No 4 October 1983 A B C Fig 2. (Patient 7.) Tomogrums: (A) The tumor is situated close to the apex of the right thorax.

tered through the bed of the fourth rib; the neck of the third rib was transected for adequate exposure. The first dorsal nerve emerged from the upper portion of the tumor and was divided.

3 404 The Annals of Thoracic Surgery Vol 36 No 4 October 1983 A B C Fig 2. (Patient 7.) Tomogrums: (A) The tumor is situated close to the apex of the right thorax. (B) Anteroposterior view shows the eroded vertebral body (arrows). (C) Oblique view demonstrates the enlarged foramen (arrows). tered through the bed of the fourth rib; the neck of the third rib was transected for adequate exposure. The first dorsal nerve emerged from the upper portion of the tumor and was divided. The tumor extended as a stalk 1.5 cm in diameter into the intervertebral foramen between T-1 and T-2. Laminectomy was done at this level. The first dorsal root was exposed and divided. The tumor was lifted out of the chest, passing the spinal portion through the enlarged foramen. A pleural flap was sutured over the foramen. The tumor removed was a 6 cm schwannoma. The patient s postoperative course was complicated by a superficial wound infection, which healed satisfactorily. PATIENT 3. A 63-year-old woman experienced progressive left-sided chest pain. A paraspinal mass with erosion of the pedicle of T-9 was identified. Computed tomographic scan showed narrowing of the spinal canal at T-9 (Fig 3A). Myelogram with metrizamide and tomograms showed an extradural lesion extending from T-8 to T-10, invaginating into the subarachnoid space (F& 3~). Arteriogram showed an enlarged ninth intercostal artery supplying the tumor. The artery of Adamkiewicz to the

405 Grillo et al: "Dumbbell" Intrathoracic and Intraspinal Tumors A B Fils 3. (Patient 3.) (A) Computed tomographic scan shows destruction of the pedicle and intraspinal imagination by the tumor mass.

4 405 Grillo et al: "Dumbbell" Intrathoracic and Intraspinal Tumors A B Fils 3. (Patient 3.) (A) Computed tomographic scan shows destruction of the pedicle and intraspinal imagination by the tumor mass. (B) Myelogram with metrizamide demonstrates that the spinal canal is obviously narrowed. The arrow points to the location of the enlarged foramen. Note the eroded pedicle. spinal cord arose from the left L-1 lumbar artery. The vertical limb of the operative incision was centered at T-9, and the transverse portion extended to the tip of the eleventh rib. The ninth rib was resected. The intercostal nerve entering the tumor was divided and the mass freed into the foramen. Laminectomies of T-8 and T-9 permitted access for removal of the extradural tumor. The T-9 nerve root was divided. Diagnosis was schwannoma. Convalescence was uneventful. PATIENT 4. A 24-year-old man was found to have an asymptomatic mass in the left hemithorax. Retrospective review showed a smaller mass present four years before. The patient had small cafe au lait spots and subcutaneous nodules in the neck. Neurological examination was negative. Tomograms showed enlargement of the foramen at the T-1 and T-2 levels. A myelogram was normal. Surgical approach was through the bed of the excised fourth rib using the incision described. The tumor extended into the foramen between the first and second vertebrae and was attached also to the brachial plexus. The second intercostal nerve was sectioned with the tumor, and the mass was dissected from the brachial plexus. It was possible to dissect the extension from the foramen and divide the nerve proximally as it entered the tumor. Laminectomy was not necessary for complete removal. The pathological diagnosis was neurofibroma. The tumor measured 4 cm in its greatest diameter. Comment One of the first comprehensive reviews of these neurogenic tumors in the English-language literature was by Heuer [2] in He referred to these lesions as hourglass tumors of the spine, as did Naffziger and Brown [3] in Love and Dodge [4] in 1952 were the investigators who used the term dumbbell in describing spinal canal involvement. In their comprehensive report published in 1978, Akwari and colleagues [l] listed a variety of previous approaches to this problem. Davidson and co-workers [5] found 8 patients with intervertebral foramina1 extension

406 The Annals of Thoracic Surgery Vol 36 No 4 October 1983 out of 55 patients who had intrathoracic neural tumors. Three of the 8 underwent laminectomy later.

5 406 The Annals of Thoracic Surgery Vol 36 No 4 October 1983 out of 55 patients who had intrathoracic neural tumors. Three of the 8 underwent laminectomy later. The authors proposed the somewhat unsatisfactory program of pursuing residual tumor at the foramen in a second operation only if a tumor mass was demonstrated on myelography. Irger and colleagues [6] described successful application in 10 patients of a singlestage technique utilizing lateral or anterolateral transpleural thoracotomy and laminectomy. LeBrigand [7] counseled a similar approach for tumors en sablier. In their report, Akwari and associates [l] presented the cases of 19 patients with dumbbell mediastinal neurogenic tumors. Nine patients had staged resection with laminectomy first and thoracotomy at a later date. A single-stage combined resection was performed in 7 patients. The authors indicated that this was their preferred practice. With the patient prone, they used a vertical, curvilinear incision over the midline of the back, centered at the level of the tumor. The paravertebral muscles were reflected laterally on the side of the tumor. After laminectomy was done, a segment of rib was removed to expose the intrathoracic tumor from behind. We believe that the approach we have outlined provides better visualization of the pathological involvement. Further, in a patient such as our fourth, laminectomy proved to be unnecessary. In neither our series nor that of Akwari and colleagues [I] were serious postoperative complications encountered. It seems clear that a single-stage combined resection is the procedure of choice in patients with this configuration of tumor. Preoperative definition is essential. References 1. Akwari OE, Payne WS, Onofrio BM, et al: Dumbbell neurogenic tumors of the mediastinum. Mayo Clin Proc 53:353, Heuer GJ: The so-called hour-glass tumors of the spine. Arch Surg 18:935, Naffziger HC, Brown HA: Hour-glass tumors of the spine. Arch Neurol Psychiatr 29:561, Love JG, Dodge HW Jr: Dumbbell (hourglass) neurofibromas affecting the spinal cord. Surg Gynecol Obstet 94:161, Davidson KG, Walbaum PR, McCormack JM: Intrathoracic neural tumours. Thorax 33:359, 1978 Irger IM, Perelman MI, Koroleva NS, et al: Surgical tactics in hour-glass tumor of intervertebralmediastinal localization. Vopr Neirokhir (Moscow) 5:3, 1980 LeBrigand H: Nouveau traite de technique chirurgicale. Paris, Masson, 1973, vol 3, pp Discussion DR. W. SPENCER PAYNE (Rochester, MN): Dr. Grillo and his colleagues are to be commended for bringing this important subject before us. Most of what has been published on these tumors has appeared in general medical and neurosurgical literature, not the literature specifically for thoracic surgeons who most commonly deal with the problem. The important message is that unless a dumbbell neurogenic tumor is recognized prior to operation, there is risk that removal of just the intrathoracic portion may be followed by paraplegia or other sequelae of permanent spinal cord injury. According to Wychulis and associates, neurogenic tumors are the most common of the mediastinal tumors (J Thorac Cardiovasc Surg 62:379, 1971). As Dr. Grillo and his associates have indicated, approximately 8% of the posterior mediastinal neurogenic tumors are dumbbell in configuration and often without cord symptoms. I reemphasize that in the asymptomatic patient, it is only by means of special roentgenographic views of the spine or by computed tomographic scan that the presence of the dumbbell tumor can be suspected. The demonstration on roentgenograms of bony erosion of vertebral pedicles or lamina, or enlargement of the intervertebral foramen in association with a posterior mediastinal mass is an indication for neurosurgical collaboration and myelography. Myelography is still the most definitive means of establishing intraspinal extension. I do not know of any examples of patients in whom a dumbbell tumor has existed without the bony erosions. Once a dumbbell tumor is diagnosed by myelography, a planned, combined, single-stage procedure with neurosurgery is carried out to remove both the intraspinal and mediastinal masses at one sitting. Two-stage procedures have carried major risk of cord injury irrespective of which portion is removed first. If the intraspinal tumor is extensive, a laminectomy will be required. Many such tumors, however, are quite localized, and a lateral, extrapleural approach to the spinal cord can be made at the time of extrapleural posterior rib resection for exposure. The rib segment can be used as a bone graft for spinal fusion at the conclusion of the procedure. It should be noted that spinal operations may interfere with bone growth in the young, especially in those in whom more than one to two years of growth can be anticipated. Orthopedic consultation should be obtained to assist in minimizing late development of kyphoscoliosis in these younger, growing patients. Again, I commend Dr. Grillo and his colleagues for

407 Grillo et al: Dumbbell Intrathoracic and Intraspinal Tumors bringing this important subject to the attention of The Society of Thoracic Surgeons. DR. JOHN R.

6 407 Grillo et al: Dumbbell Intrathoracic and Intraspinal Tumors bringing this important subject to the attention of The Society of Thoracic Surgeons. DR. JOHN R. PELLETT (Madison, WI): In the past fifteen months at the University Hospital in Madison, my associates and I have encountered 4 neurogenic tumors, 2 of which had a major intraspinal component and one that also had substantial involvement of the brachial plexus. A 13-year-old girl was seen at the local hospital with a history of appendicitis. This condition subsequently was taken care of. When she was seen by us, bony erosion from pressure and widening of the foramina were present. The obvious conclusion was that there was going to be an intraspinal component. The second patient was only 2 years old. She had a very small apical tumor in this location. She also had Horner s syndrome and a weak foot. A computed tomographic scan demonstrated the substantial size of the lesion. The bronchus was distorted forward. There was erosion of the rib and enlargement of the intervertebral foramina. I agree that it is extremely important and imperative that the thoracic surgical team work with its neurosurgical colleagues from the start. In our patients, they were intimately involved in the care and management of the operation. The details of the operation have already been described nicely by Dr. Grillo and his co-workers. We selected a posterolateral thoracotomy incision with a slightly further extent posteriorly. The tumors can be completely resected. We prefer to do the laminectomy through the lateral approach. In 2 of our patients, the operation was done easily and there was total recovery. DR. LYMAN A. BREWER (Loma Linda, CA): The authors have made an excellent presentation. Dr. Donald Mulder and I have removed 2 dumbbell neurogenic tumors of the spinal cord (out of a series of 50 patients) and l recurrent chondrosarcoma. I have three points to make. Adherence to these principles will improve results. First, complete single-stage combined removal of the mediastinal and spinal portions of the tumor is mandatory, as stated by Dr. Grillo and his associates. If the intraspinal portion is left in situ, it may become edematous and cause further neurological deficit. Second, continued intrapleural leakage of the spinal fluid may cause dehydration, sepsis, and even death. Therefore, the defect in the dura mater must be closed. We have found our pedicled pericardial fatgraft, which has been so successful in reinforcing the bronchial stump in pulmonary resection, very effective for sealing the dura. Pleura, muscle grafts, and omentum have also been used. Third, if resection of the osseus spine has been extensive, spine stabilization will prevent kyphosis. In a patient with a chondrosarcoma dumbbell tumor, we employed two rib struts, followed up later by a brace to stabilize the thoracic spine. This is particularly important in children, because their rapid growth makes the development of kyphosis more likely. DR. GRILLO: I thank Drs. Payne, Pellett, and Brewer for their further pertinent exposition of this dynamite-laden entity, which is rare in any one surgeon s experience. If we as surgeons consider the mediastinal tumors we treat in a year, how many are neurogenic and, of these patients, how many have this problem? Dr. Brewer, we close the spinal canal with a pleural flap to prevent leakage. I reviewed five well-known thoracic surgical textbooks (three published in the United States, one in Britain, and one in France) for their recommendations about dumbbell tumors. The three American textbooks are not at all clear on what to do. Gibbon mentions nothing on this topic at all. Glenn s book, the latest edition of which is just off the press, advises two operations, first a neurosurgical and then a thoracic one. If the diagnosis is made preoperatively, Shields suggests first a neurosurgical and later a thoracic procedure. If a diagnosis is not made, it is a little unclear what the surgeon is advised to do-just muddle through as best as he or she can. D Abreu s book, a British textbook, in a brief note recommends against a two-stage approach. There s a single illustrative case report. The clearest statement is in LeBrigands French textbook. With Gallic logic, he tells the surgeon precisely what to do and includes a warning to look out for the artery of Adamkiewicz.

Open surgery for posterior mediastinal neurogenic tumors

Review Article Page 1 of 5 Open surgery for posterior mediastinal neurogenic tumors Erkan Kaba 1, Mazen Rasmi Alomari 2, Alper Toker 2 1 Department of Thoracic Surgery, Istanbul Bilim University Medical